Conductive polishing article for electrochemical mechanical polishing

ABSTRACT

Embodiments of a polishing article for polishing a substrate are provided. In one embodiment, the polishing article includes a ring-shaped upper layer having a polishing surface, and a conductive layer coupled to the upper layer and forming a replaceable assembly therewith.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/642,128, filed Aug. 15, 2003 now U.S. Pat. No. 6,962,524, which is acontinuation-in-part of U.S. patent application Ser. No. 10/608,513,filed Jun. 26, 2003 (hereinafter referred to as the “'513 application”),which is a continuation-in-part of U.S. patent application Ser. No.10/140,010, filed May 7, 2002 now U.S. Pat. No. 6,979,248. The '513application is also a continuation-in-part of U.S. patent applicationSer. No. 10/211,626, filed Aug. 2, 2002 now U.S. Pat. No. 7,125,477,which is a continuation-in-part of U.S. patent application Ser. No.10/033,732, filed Dec. 27, 2001 now U.S. Pat. No. 7,066,800, which is acontinuation-in-part of U.S. patent application Ser. No. 09/505,899,filed Feb. 17, 2000 now U.S. Pat. No. 6,537,144. The '513 application isadditionally a continuation-in-part of U.S. patent application Ser. No.10/210,972, filed Aug. 2, 2002, which is also a continuation-in-part ofU.S. patent application Ser. No. 09/505,899, filed Feb. 17, 2000 nowU.S. Pat. No. 6,537,144. The '513 application is furthercontinuation-in-part of U.S. patent application Ser. No. 10/151,538,filed May 16, 2002. This application is also a continuation-in-part ofU.S. patent application Ser. No. 10/244,697, filed Sep. 16, 2002 nowU.S. Pat. No. 6,991,526, a continuation-in-part of U.S. application Ser.No. 10/244,688, filed Sep. 16, 2002 now U.S. Pat. No. 6,848,970, and acontinuation-in-part of U.S. patent application Ser. No. 10/391,324,filed Mar. 18, 2003. All of the above referenced applications are herebyincorporated by reference in their entireties.

This application is additionally related to U.S. patent application Ser.No. 10/033,732, filed on Dec. 27, 2001; U.S. patent application Ser. No.10/455,491, filed Jun. 6, 2003; and U.S. patent application Ser. No.10,455,895, filed Jun. 6, 2003, all of which are also incorporatedherein by reference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an article of manufacture and apparatusfor planarizing a substrate surface.

2. Background of the Related Art

Sub-quarter micron multi-level metallization is one of the keytechnologies for the next generation of ultra large-scale integration(ULSI). The multilevel interconnects that lie at the heart of thistechnology require planarization of interconnect features formed in highaspect ratio apertures, including contacts, vias, lines and otherfeatures. Reliable formation of these interconnect features is veryimportant to the success of ULSI and to the continued effort to increasecircuit density and quality on individual substrates and die.

In the fabrication of integrated circuits and other electronic devices,multiple layers of conducting, semiconducting, and dielectric materialsare deposited on or removed from a surface of a substrate. Thin layersof conducting, semiconducting, and dielectric materials may be depositedby a number of deposition techniques. Common deposition techniques inmodern processing include physical vapor deposition (PVD), also known assputtering, chemical vapor deposition (CVD), plasma-enhanced chemicalvapor deposition (PECVD), and electrochemical plating (ECP).

As layers of materials are sequentially deposited and removed, theuppermost surface of the substrate may become non-planar across itssurface and require planarization. Planarizing a surface, or “polishing”a surface, is a process where material is removed from the surface ofthe substrate to form a generally even, planar surface. Planarization isuseful in removing undesired surface topography and surface defects,such as rough surfaces, agglomerated materials, crystal lattice damage,scratches, and contaminated layers or materials. Planarization is alsouseful in forming features on a substrate by removing excess depositedmaterial used to fill the features and to provide an even surface forsubsequent levels of metallization and processing.

Chemical mechanical planarization, or chemical mechanical polishing(CMP), is a common technique used to planarize substrates. CMP utilizesa chemical composition, typically a slurry or other fluid medium, forselective removal of material from substrates. In conventional CMPtechniques, a substrate carrier or polishing head is mounted on acarrier assembly and positioned in contact with a polishing pad in a CMPapparatus. The carrier assembly provides a controllable pressure to thesubstrate urging the substrate against the polishing pad. The pad ismoved relative to the substrate by an external driving force. The CMPapparatus effects polishing or rubbing movement between the surface ofthe substrate and the polishing pad while dispersing a polishingcomposition to effect chemical activity and/or mechanical activity andconsequential removal of material from the surface of the substrate.

One material increasingly utilized in integrated circuit fabrication iscopper due to its desirable electrical properties. However, copper hasits own special fabrication problems. For example, copper is difficultto pattern and etch and new processes and techniques, such as damasceneor dual damascene processes, are being used to form copper substratefeatures.

In damascene processes, a feature is defined in a dielectric materialand subsequently filled with copper. Dielectric materials with lowdielectric constants, i.e., less than about 3, are being used in themanufacture of copper damascenes. Barrier layer materials are depositedconformally on the surfaces of the features formed in the dielectriclayer prior to deposition of copper material. Copper material is thendeposited over the barrier layer and the surrounding field. However,copper fill of the features usually results in excess copper material,or overburden, on the substrate surface that must be removed to form acopper filled feature in the dielectric material and prepare thesubstrate surface for subsequent processing.

One challenge that is presented in polishing copper materials is thatthe interface between the conductive material and the barrier layer isgenerally non-planar and residual copper material is retained inirregularities formed by the non-planar interface. Further, theconductive material and the barrier materials are often removed from thesubstrate surface at different rates, both of which can result in excessconductive material being retained as residues on the substrate surface.Additionally, the substrate surface may have different surfacetopography, depending on the density or size of features formed therein.Copper material is removed at different removal rates along thedifferent surface topography of the substrate surface, which makeseffective removal of copper material from the substrate surface andfinal planarity of the substrate surface difficult to achieve.

One solution to remove all of the desired copper material from thesubstrate surface is to overpolish the substrate surface. However,overpolishing of some materials can result in the formation oftopographical defects, such as concavities or depressions in features,referred to as dishing, or excessive removal of dielectric material,referred to as erosion. The topographical defects from dishing anderosion can further lead to non-uniform removal of additional materials,such as barrier layer materials disposed thereunder, and produce asubstrate surface having a less than desirable polishing quality.

Another problem with the polishing of copper surfaces arises from theuse of low dielectric constant (low k) dielectric materials to formcopper damascenes in the substrate surface. Low k dielectric materials,such as carbon doped silicon oxides, may deform or fracture underconventional polishing pressures (i.e., about 6 psi), called downforce,which can detrimentally affect substrate polish quality anddetrimentally affect device formation. For example, relative rotationalmovement between the substrate and a polishing pad can induce a shearforce along the substrate surface and deform the low k material to formtopographical defects, which can detrimentally affect subsequentpolishing.

One solution for polishing copper in low dielectric materials is bypolishing copper by electrochemical mechanical polishing (ECMP)techniques. ECMP techniques remove conductive material from a substratesurface by electrochemical dissolution while concurrently polishing thesubstrate with reduced mechanical abrasion compared to conventional CMPprocesses. The electrochemical dissolution is performed by applying abias between a cathode and substrate surface to remove conductivematerials from a substrate surface into a surrounding electrolyte.

In one embodiment of an ECMP system, the bias is applied by a ring ofconductive contacts in electrical communication with the substratesurface in a substrate support device, such as a substrate carrier head.However, the contact ring has been observed to exhibit non-uniformdistribution of current over the substrate surface, which results innon-uniform dissolution, especially during overpolishing where a ring ofconductive contacts doesn't efficiently remove residues. Mechanicalabrasion is performed by contacting the substrate with a conventionalpolishing pad and providing relative motion between the substrate andpolishing pad. However, conventional polishing pads often limitelectrolyte flow to the surface of the substrate. Additionally, thepolishing pad may be composed of insulative materials that may interferewith the application of bias to the substrate surface and result innon-uniform or variable dissolution of material from the substratesurface.

As a result, there is a need for an improved polishing article for theremoval of conductive material on a substrate surface.

SUMMARY OF THE INVENTION

Aspects of the invention generally provide an article of manufacture andan apparatus for planarizing a layer on a substrate usingelectrochemical deposition techniques, electrochemical dissolutiontechniques, polishing techniques, and/or combinations thereof.

In one aspect, a polishing article for polishing a substrate includes abody having a surface adapted to polish the substrate and at least oneconductive element embedded at least partially in the body. Theconductive element may include fibers coated with a conductive material,a conductive filler, or combinations thereof, which may be disposed in abinder material. The conductive element may include a fabric ofinterwoven fibers coated with the conductive material embedded at leastpartially in the body, a composite of fibers coated with the conductivematerial, conductive fillers, or combinations thereof, and a binder,embedded at least partially in the body, or combinations thereof. Theconductive element may have a contact surface that extends beyond aplane defined by the polishing surface and may comprise a coil, one ormore loops, one or more strands, an interwoven fabric of materials, orcombinations thereof. A plurality of perforations and a plurality ofgrooves may be formed in the polishing article to facilitate flow ofmaterial through and across the polishing article.

In another aspect, a polishing article is provided for processing asubstrate surface, such as a conductive layer deposited on the substratesurface. The polishing article include a body comprising at least aportion of fibers coated with a conductive material, conductive fillers,or combinations thereof, and adapted to polish the substrate. Aplurality of perforations and a plurality of grooves may be formed inthe polishing article to facilitate flow of material through and aroundthe polishing article.

In another aspect, the polishing articles may be disposed in anapparatus for processing a substrate including a basin, a permeable discdisposed in the basin, the polishing article or the article ofmanufacture disposed on the permeable disk, an electrode disposed in thebasin between the permeable disc and the bottom of the basin, and apolishing head adapted to retain the substrate during processing.

In another aspect, the polishing articles may be used as a conductivepolishing article in a method for processing a substrate includingproviding an apparatus containing an enclosure, disposing a conductivepolishing article in the enclosure, supplying an electrically conductivesolution to the enclosure at a flow rate up to about 20 gallons perminute (GPM), positioning the substrate adjacent the conductivepolishing article in the electrically conductive solution, contacting asurface of the substrate with the conductive polishing article in theelectrically conductive solution, applying a bias between an electrodeand the conductive polishing article, and removing at least a portion ofthe surface of the substrate surface.

In another embodiment of the invention, a polishing article forprocessing a substrate comprises a fabric layer having a conductivelayer disposed thereover. The conductive layer has an exposed surfaceadapted to polish a substrate. The fabric layer may be woven ornon-woven. The conductive layer may be comprised of a soft conductivematerial and, in one embodiment, the exposed surface may be planar orembossed.

In another embodiment of the invention, a polishing article forprocessing a substrate comprises a conductive fabric layer having aconductive layer disposed thereover. The conductive layer has an exposedsurface adapted to polish a substrate. The conductive fabric layer maybe woven or non-woven. The conductive layer may be comprised of a softconductive material and, in one embodiment, the exposed surface may beplanar or embossed.

In another embodiment of the invention, a polishing article forprocessing a substrate comprises a conductive fabric layer having anonconductive layer disposed thereover. The nonconductive layer has anexposed surface adapted to polish a substrate with at least partiallyexposed conductive fabric to positively bias polishing substrate. Theconductive fabric layer may be woven or non-woven. The nonconductivelayer may be comprised of an abrasive material and, in one embodiment,the exposed surface may be planar or embossed.

In another embodiment of the invention, a polishing article forprocessing a substrate comprises a conductive portion having abrasiveelements extending therefrom. In another embodiment of the invention, apolishing article for processing a substrate comprises conductiveportion having conductive rollers extending therefrom. In oneembodiment, the conductive rollers have a polymer core at leastpartially covered by a conductive coating that is comprised of a softconductive material.

In another embodiment, a polishing article for processing a substratecomprises a ring-shaped upper layer having a polishing surface and aconductive layer. The ring-shaped upper layer and the conductive layerare coupled to form a replaceable assembly.

In another aspect, a ball assembly is provided. In one embodiment, theball assembly includes a housing, a ball, a conductive adapter and acontact element. The housing has an annular seat extending into a firstend of an interior passage. The conductive adapter is coupled to asecond end of the housing. The contact element electrically couples theadapter and the ball with is retained in the housing between seat andthe adapter.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited aspects of the inventionare attained and can be understood in detail, a more particulardescription of the invention, briefly summarized above, may be had byreference to embodiments thereof which are illustrated in the appendeddrawings.

It is to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and, therefore, are not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a plan view of one embodiment of a processing apparatus of theinvention;

FIG. 2 is a sectional view of one embodiment of an ECMP station;

FIG. 3 is a partial cross-sectional view of one embodiment of apolishing article;

FIG. 4 is a top plan view of one embodiment of a grooved polishingarticle;

FIGS. 5-6 are top plan views of embodiments of a grooved polishingarticle;

FIG. 7A is a top view of a conductive cloth or fabric described herein;

FIGS. 7B and 7C are partial cross-sectional views of polishing articleshaving a polishing surface comprising a conductive cloth or fabric;

FIG. 7D is a partial cross-sectional view of one embodiment of apolishing article including a metal foil;

FIG. 7E is another embodiment of a polish article comprising a fabricmaterial;

FIG. 7F is another embodiment of a polish article having a window formedtherein;

FIGS. 8A and 8B are top and cross-section schematic views, respectively,of one embodiment of a polishing article having a conductive element;

FIGS. 8C and 8D are top and cross-section schematic views, respectively,of one embodiment of a polishing article having a conductive element;

FIGS. 9A and 9B are perspective views of other embodiments of apolishing article having a conductive element;

FIG. 10A is a partial perspective view of another embodiment of apolishing article;

FIG. 10B is a partial perspective view of another embodiment of apolishing article;

FIG. 10C is a partial perspective view of another embodiment of apolishing article;

FIG. 10D is a partial perspective view of another embodiment of apolishing article;

FIG. 10E is a partial perspective view of another embodiment of apolishing article;

FIGS. 11A-11C are schematic side views of one embodiment of a substratecontacting one embodiment of a polishing article described herein;

FIGS. 12A-12D are top and side schematic views of embodiments of apolishing article having extensions connected to a power source;

FIGS. 12E and 12F show side schematic and exploded perspective views ofanother embodiment of providing power to a polishing article;

FIGS. 13A-B are top and sectional views of another embodiment of aconductive article;

FIGS. 14A-D are top and sectional views of another embodiment of aconductive article;

FIGS. 15-17 are a sectional view of alternate embodiments of aconductive article;

FIG. 18 is sectional view of another embodiment of a conductive articlehaving one embodiment of a ball assembly; and

FIGS. 19A-B are side and exploded views of the ball assembly of FIG. 18;

FIG. 20 is one embodiment of a contact element of the ball assembly ofFIGS. 18 and 19A-B;

FIGS. 21-23 are perspective and sectional views of another embodiment ofa conductive article having another embodiment of a ball assembly; and

FIGS. 24A-B are bottom views of alternate embodiments of an electrodethat may advantageously adapted for use with different embodiments ofconductive articles.

To facilitate understanding, identical reference numerals have beenused, wherever possible, to designate identical elements that are commonto the figures.

DETAILED DESCRIPTION

The words and phrases used herein should be given their ordinary andcustomary meaning in the art by one skilled in the art unless otherwisefurther defined. Chemical-mechanical polishing should be broadlyconstrued and includes, but is not limited to, abrading a substratesurface by chemical activity, mechanical activity, or a combination ofboth chemical and mechanical activity. Electropolishing should bebroadly construed and includes, but is not limited to, planarizing asubstrate by the application of electrochemical activity, such as byanodic dissolution.

Electrochemical mechanical polishing (ECMP) should be broadly construedand includes, but is not limited to, planarizing a substrate by theapplication of electrochemical activity, chemical activity, mechanicalactivity, or a combination of electrochemical, chemical, and mechanicalactivity to remove material from a substrate surface.

Electrochemical mechanical plating process (ECMPP) should be broadlyconstrued and includes, but is not limited to, electrochemicallydepositing material on a substrate and generally planarizing thedeposited material by the application of electrochemical activity,chemical activity, mechanical activity, or a combination ofelectrochemical, chemical, and mechanical activity.

Anodic dissolution should be broadly construed and includes, but is notlimited to, the application of an anodic bias to a substrate directly orindirectly which results in the removal of conductive material from asubstrate surface and into a surrounding electrolyte solution. Polishingsurface is broadly defined as the portion of an article of manufacturethat at least partially contacts a substrate surface during processingor electrically couples an article of manufacture to a substrate surfaceeither directly through contact or indirectly through an electricallyconductive medium.

Polishing Apparatus

FIG. 1 depicts a processing apparatus 100 having at least one stationsuitable for electrochemical deposition and chemical mechanicalpolishing, such as electrochemical mechanical polishing (ECMP) station102 and at least one conventional polishing or buffing station 106disposed on a single platform or tool. One polishing tool that may beadapted to benefit from the invention is a MIRRA® Mesa™ chemicalmechanical polisher available from Applied Materials, Inc. located inSanta Clara, Calif.

For example, in the apparatus 100 shown in FIG. 1, the apparatus 100includes two ECMP stations 102 and one polishing station 106. Thestations may be used for processing a substrate surface. For example, asubstrate having feature definitions formed therein and filled with abarrier layer and then a conductive material disposed over the barrierlayer may have the conducive material removed in two steps in the twoECMP stations 102 with the barrier layer polished in the polishingstation 106 to form a planarized surface.

The exemplary apparatus 100 generally includes a base 108 that supportsone or more ECMP stations 102, one or more polishing stations 106, atransfer station 110 and a carousel 112. The transfer station 110generally facilitates transfer of substrates 114 to and from theapparatus 100 via a loading robot 116. The loading robot 116 typicallytransfers substrates 114 between the transfer station 110 and a factoryinterface 120 that may include a cleaning module 122, a metrology device104 and one or more substrate storage cassettes 118. One example of ametrology device 104 is a NovaScan™ Integrated Thickness Monitoringsystem, available from Nova Measuring Instruments, Inc., located inPhoenix, Ariz.

Alternatively, the loading robot 116 (or factory interface 120) maytransfer substrates to one or more other processing tools (not shown)such as a chemical vapor deposition tool, physical vapor depositiontool, etch tool and the like.

In one embodiment, the transfer station 110 comprises at least an inputbuffer station 124, an output buffer station 126, a transfer robot 132,and a load cup assembly 128. The loading robot 116 places the substrate114 onto the input buffer station 124. The transfer robot 132 has twogripper assemblies, each having pneumatic gripper fingers that hold thesubstrate 114 by the substrate's edge. The transfer robot 132 lifts thesubstrate 114 from the input buffer station 124 and rotates the gripperand substrate 114 to position the substrate 114 over the load cupassembly 128, then places the substrate 114 down onto the load cupassembly 128.

The carousel 112 generally supports a plurality of polishing heads 130,each of which retains one substrate 114 during processing. The carousel112 transfers the polishing heads 130 between the transfer station 110,the one or more ECMP stations 102 and the one or more polishing stations106. One carousel 112 that may be adapted to benefit from the inventionis generally described in U.S. Pat. No. 5,804,507, issued Sep. 8, 1998to Tolles et al., which is hereby incorporated by reference in itsentirety.

Generally, the carousel 112 is centrally disposed on the base 108. Thecarousel 112 typically includes a plurality of arms 138. Each arm 138generally supports one of the polishing heads 130. One of the arms 138depicted in FIG. 1 is not shown so that the transfer station 110 may beseen. The carousel 112 is indexable such that the polishing head 130 maybe moved between the stations 102, 106 and the transfer station 110 in asequence defined by the user.

Generally the polishing head 130 retains the substrate 114 while thesubstrate 114 is disposed in the ECMP station 102 or polishing station106. The arrangement of the ECMP stations 106 and polishing stations 102on the apparatus 100 allow for the substrate 114 to be sequentiallyplated or polished by moving the substrate between stations while beingretained in the same polishing head 130. One polishing head that may beadapted to the invention is a TITAN HEAD™ substrate carrier,manufactured by Applied Materials, Inc., located in Santa Clara, Calif.

Examples of embodiments of polishing heads 130 that may be used with thepolishing apparatus 100 described herein are described in U.S. Pat. No.6,183,354, issued Feb. 6, 2001 to Zuniga, et al., which is herebyincorporated by reference in its entirety.

To facilitate control of the polishing apparatus 100 and processesperformed thereon, a controller 140 comprising a central processing unit(CPU) 142, memory 144, and support circuits 146, is connected to thepolishing apparatus 100. The CPU 142 may be one of any form of computerprocessor that can be used in an industrial setting for controllingvarious drives and pressures. The memory 144 is connected to the CPU142. The memory 144, or computer-readable medium, may be one or more ofreadily available memory such as random access memory (RAM), read onlymemory (ROM), floppy disk, hard disk, or any other form of digitalstorage, local or remote. The support circuits 146 are connected to theCPU 142 for supporting the processor in a conventional manner. Thesecircuits include cache, power supplies, clock circuits, input/outputcircuitry, subsystems, and the like.

Power to operate the polishing apparatus 100 and/or the controller 140is provided by a power supply 150. Illustratively, the power supply 150is shown connected to multiple components of the polishing apparatus100, including the transfer station 110, the factory interface 120, theloading robot 116 and the controller 140. In other embodiments separatepower supplies are provided for two or more components of the polishingapparatus 100.

FIG. 2 depicts a sectional view of the polishing head 130 supportedabove an ECMP station 102. The ECMP station 102 generally includes abasin 202, an electrode 204, polishing article 205, a disc 206 and acover 208. In one embodiment, the basin 202 is coupled to the base 108of the polishing apparatus 100. The basin 202 generally defines acontainer or electrolyte cell in which a conductive fluid such as anelectrolyte 220 can be confined. The electrolyte 220 used in processingthe substrate 114 can be used to process metals such as copper,aluminum, tungsten, gold, silver, or any other materials that can beelectrochemically deposited onto or electrochemically removed from thesubstrate 114.

The basin 202 can be a bowl shaped member made of a plastic such asfluoropolymers, polytetrafluoroethylene, PFA, PE, PES, or othermaterials that are compatible with electroplating and electropolishingchemistries. The basin 202 has a bottom 210 that includes an aperture216 and a drain 214. The aperture 216 is generally disposed in thecenter of the bottom 210 and allows a shaft 212 to pass therethrough. Aseal 218 is disposed between the aperture 216 and the shaft 212 andallows the shaft 212 to rotate while preventing fluids disposed in thebasin 202 from passing through the aperture 216.

The basin 202 typically includes the electrode 204, the disc 206, andthe polishing article 205 disposed therein. Polishing article 205, suchas a polishing pad, is disposed and supported in the basin 202 on thedisc 206.

The electrode 204 is a counter-electrode to the substrate 114 and/orpolishing article 205 contacting a substrate surface. The polishingarticle 205 is at least partially conductive and may act as an electrodein combination with the substrate during electrochemical processes, suchas an electrochemical mechanical plating process (ECMPP), which includeselectrochemical deposition and chemical mechanical polishing, orelectrochemical dissolution. The electrode 204 may be an anode orcathode depending upon the positive bias (anode) or negative bias(cathode) applied between the electrode 204 and polishing article 405.

For example, depositing material from an electrolyte on the substratesurface, the electrode 204 acts as an anode and the substrate surfaceand/or polishing article 205 acts as a cathode. When removing materialfrom a substrate surface, such as by dissolution from an applied bias,the electrode 204 functions as a cathode and the substrate surfaceand/or polishing article 205 may act as an anode for the dissolutionprocess.

The electrode 204 is generally positioned between the disc 206 and thebottom 210 of the basin 202 where it may be immersed in or exposed tothe electrolyte 220. The electrode 204 may be fabricated from amagnetically coupleable material to allow for the electrode to besecured to the platen. The electrode 204 can be a plate-like member, aplate having multiple apertures formed therethrough, or a plurality ofelectrode pieces disposed in a permeable membrane or container. Apermeable membrane (not shown) may be disposed between the disc 206 andthe electrode 204 or electrode 204 and polishing article 205 to filterbubbles, such as hydrogen bubbles, form the wafer surface and to reducedefect formation and stabilize or more uniformly apply current or powertherebetween.

For electrodeposition processes, the electrode 204 is made of thematerial to be deposited or removed, such as copper, aluminum, gold,silver, tungsten and other materials which can be electrochemicallydeposited on the substrate 114. For electrochemical removal processes,such as anodic dissolution, the electrode 204 may include anon-consumable electrode of a material other than the depositedmaterial, for example, platinum, carbon, or aluminum, for copperdissolution.

The polishing article 205 can be a pad, a web or a belt of material,which is compatible with the fluid environment and the processingspecifications. In the embodiment depicted in FIG. 2, the polishingarticle 205 is circular in form and positioned at an upper end of thebasin 202, supported on its lower surface by the disc 206. The polishingarticle 205 includes at least a partially conductive surface of aconductive material, such as one or more conductive elements, forcontact with the substrate surface during processing. The polishingarticle 205 may be a portion or all of a conductive polishing materialor a composite of a conductive polishing material embedded in ordisposed on a conventional polishing material. For example theconductive material may be disposed on a “backing” material disposedbetween the disc 206 and polishing article 205 to tailor the complianceand/or durometer of the polishing article 205 during processing.

The basin 202, the cover 208, and the disc 206 may be movably disposedon the base 108. The basin 202, cover 208 and disc 206 may be axiallymoved toward the base 108 to facilitate clearance of the polishing head130 as the carousel 112 indexes the substrate 114 between the ECMP andpolishing stations 102, 106. The disc 206 is disposed in the basin 202and coupled to the shaft 212. The shaft 212 is generally coupled to amotor 224 disposed below the base 108. The motor 224, in response to asignal from the controller 140, rotates the disc 206 at a predeterminedrate.

The disc 206 may be a perforated article support made from a materialcompatible with the electrolyte 220 which would not detrimentally affectpolishing. The disc 206 may be fabricated from a polymer, for examplefluoropolymers, PE, polytetrafluoroethylene, PFA, PES, HDPE, UHMW or thelike. The disc 206 can be secured in the basin 202 using fasteners suchas screws or other means such as snap or interference fit with theenclosure, being suspended therein and the like. The disc 206 ispreferably spaced from the electrode 204 to provide a wider processwindow, thus reducing the sensitivity of depositing material andremoving material from the substrate surface to the electrode 204dimensions.

The disc 206 is generally permeable to the electrolyte 220. In oneembodiment, the disc 206 includes a plurality of perforations orchannels 222 formed therein. Perforations include apertures, holes,openings, or passages formed partially or completely through an object,such as the polishing article. The perforation size and density isselected to provide uniform distribution of the electrolyte 220 throughthe disc 206 to the substrate 114.

In one aspect of the disc 206 includes perforations having a diameterbetween about 0.02 inches (0.5 millimeters) and about 0.4 inches (10mm). The perforations may have a perforation density between about 20%and about 80% of the polishing article. A perforation density of about50% has been observed to provide electrolyte flow with minimaldetrimental effects to polishing processes. Generally, the perforationsof the disc 206 and the polishing article 205 are aligned to provide forsufficient mass flow of electrolyte through the disc 206 and polishingarticle 205 to the substrate surface. The polishing article 205 may bedisposed on the disc 206 by a mechanical clamp or conductive adhesive.

While the polishing articles described herein forelectrochemical-mechanical polishing (ECMP) processes, the inventioncontemplates using the conductive polishing article in other fabricationprocesses involving electrochemical activity. Examples of such processesusing electrochemical activity include electrochemical deposition, whichinvolves the polishing article 205 being used to apply an uniform biasto a substrate surface for depositing a conductive material without theuse of conventional bias application apparatus, such as edge contacts,and electrochemical mechanical plating processes (ECMPP) that include acombination of electrochemical deposition and chemical mechanicalpolishing.

In operation, the polishing article 205 is disposed on the disc 206 inan electrolyte in the basin 202. A substrate 114 on the polishing headis disposed in the electrolyte and contacted with the polishing article205. Electrolyte is flowed through the perforations of the disc 206 andthe polishing article 205 and is distributed on the substrate surface bygrooves formed therein. Power from a power source is then applied to theconductive polishing article 205 and the electrode 204, and conductivematerial, such as copper, in the electrolyte is then removed by ananodic dissolution method.

The electrolyte 220 is flowed from a reservoir 233 into the volume 232via a nozzle 270. The electrolyte 220 is prevented from overflowing thevolume 232 by a plurality of holes 234 disposed in a skirt 254. Theholes 234 generally provide a path through the cover 208 for theelectrolyte 220 exiting the volume 232 and flowing into the lowerportion of the basin 202. At least a portion of the holes 234 aregenerally positioned between a lower surface 236 of the depression 258and the center portion 252. As the holes 234 are typically higher thanthe lower surface 236 of the depression 258, the electrolyte 220 fillsthe volume 232 and is thus brought into contact with the substrate 114and polishing medium 205. Thus, the substrate 114 maintains contact withthe electrolyte 220 through the complete range of relative spacingbetween the cover 208 and the disc 206.

The electrolyte 220 collected in the basin 202 generally flows throughthe drain 214 disposed at the bottom 210 into the fluid delivery system272. The fluid delivery system 272 typically includes the reservoir 233and a pump 242. The electrolyte 220 flowing into the fluid deliverysystem 272 is collected in the reservoir 233. The pump 242 transfers theelectrolyte 220 from the reservoir 233 through a supply line 244 to thenozzle 270 where the electrolyte 220 recycled through the ECMP station102. A filter 240 is generally disposed between the reservoir 233 andthe nozzle 270 to remove particles and agglomerated material that may bepresent in the electrolyte 220.

Electrolyte solutions may include commercially available electrolytes.For example, in copper containing material removal, the electrolyte mayinclude sulfuric acid based electrolytes or phosphoric acid basedelectrolytes, such as potassium phosphate (K₃PO₄), or combinationsthereof. The electrolyte may also contain derivatives of sulfuric acidbased electrolytes, such as copper sulfate, and derivatives ofphosphoric acid based electrolytes, such as copper phosphate.Electrolytes having perchloric acid-acetic acid solutions andderivatives thereof may also be used.

Additionally, the invention contemplates using electrolyte compositionsconventionally used in electroplating or electropolishing processes,including conventionally used electroplating or electropolishingadditives, such as brighteners among others. One source for electrolytesolutions used for electrochemical processes such as copper plating,copper anodic dissolution, or combinations thereof is Shipley Leonel, adivision of Rohm and Haas, headquartered in Philadelphia, Pa., under thetradename Ultrafill 2000. An example of a suitable electrolytecomposition is described in U.S. patent application Ser. No. 10/038,066,filed on Jan. 3, 2002, which is incorporated by reference in itsentirety.

Electrolyte solutions are provided to the electrochemical cell toprovide a dynamic flow rate on the substrate surface or between thesubstrate surface and an electrode at a flow rate up to about 20 gallonsper minute (GPM), such as between about 0.5 GPM and about 20 GPM, forexample, at about 2 GPM. It is believed that such flow rates ofelectrolyte evacuate polishing material and chemical by-products fromthe substrate surface and allow refreshing of electrolyte material forimproved polishing rates.

When using mechanical abrasion in the polishing process, the substrate114 and polishing article 205 are rotated relative to one another toremove material from the substrate surface. Mechanical abrasion may beprovided by physical contact with both conductive polishing materialsand conventional polishing materials as described herein. The substrate114 and the polishing article 205 are respectively rotated at about 5rpms or greater, such as between about 10 rpms and about 50 rpms.

In one embodiment, a high rotational speed polishing process may beused. The high rotational speed process includes rotating the polishingarticle 205 at a platen speed of about 150 rpm or greater, such asbetween about 150 rpm and about 750 rpm; and the substrate 114 may berotated at a rotational speed between about 150 rpm and about 500 rpm,such as between about 300 rpm and about 500 rpm. Further description ofa high rotational speed polishing process that may be used with thepolishing articles, processes, and apparatus described herein isdisclosed in U.S. Patent Application Ser. No. 60/308,030, filed on Jul.25, 2001, and entitled, “Method And Apparatus For Chemical MechanicalPolishing Of Semiconductor Substrates.” Other motion, including orbitalmotion or a sweeping motion across the substrate surface, may also beperformed during the process.

When contacting the substrate surface, a pressure of about 6 psi orless, such as about 2 psi or less is applied between the polishingarticle 205 and the substrate surface. If a substrate containing lowdielectric constant material is being polished, a pressure between ofabout 2 psi or less, such as about 0.5 psi or less is used to press thesubstrate 114 against the polishing article 205 during polishing of thesubstrate. In one aspect, a pressure between about 0.1 psi and about 0.2psi may be used to polishing substrates with conductive polishingarticles as described herein.

In anodic dissolution, a potential difference or bias is applied betweenthe electrode 204, performing as a cathode, and the polishing surface310 (See, FIG. 3) of the polishing article 205, performing as the anode.The substrate in contact with the polishing article is polarized via theconductive polishing surface article 310 at the same time the bias isapplied to the conductive article support member. The application of thebias allows removal of conductive material, such as copper-containingmaterials, formed on a substrate surface. Establishing the bias mayinclude the application of a voltage of about 15 volts or less to thesubstrate surface. A voltage between about 0.1 volts and about 10 voltsmay be used to dissolve copper-containing material from the substratesurface and into the electrolyte. The bias may also produce a currentdensity between about 0.1 milliamps/cm² and about 50 milliamps/cm², orbetween about 0.1 amps to about 20 amps for a 200 mm substrate.

The signal provided by the power supply 150 to establish the potentialdifference and perform the anodic dissolution process may be varieddepending upon the requirements for removing material from the substratesurface. For example, a time varying anodic signal may be provided tothe conductive polishing medium 205. The signal may also be applied byelectrical pulse modulation techniques. The electrical pulsemodification technique comprises applying a constant current density orvoltage over the substrate for a first time period, then applying aconstant reverse voltage or stopping applying a voltage over thesubstrate for a second time period, and repeating the first and secondsteps. For example, the electrical pulse modification technique may usea varying potential from between about −0.1 volts and about −15 volts tobetween about 0.1 volts and about 15 volts.

With the correct perforation pattern and density on the polishing media,it is believed that biasing the substrate from the polishing article 205provides uniform dissolution of conductive materials, such as metals,into the electrolyte from the substrate surface as compared to thehigher edge removal rate and lower center removal rate from conventionaledge contact-pins bias.

Conductive material, such as copper containing material can be removedfrom at least a portion of the substrate surface at a rate of about15,000 Å/min or less, such as between about 100 Å/min and about 15,000Å/min. In one embodiment of the invention where the copper material tobe removed is about 12,000 Å thick, the voltage may be applied to theconductive polishing article 205 to provide a removal rate between about100 Å/min and about 8,000 Å/min.

Following the electropolishing process, the substrate may be furtherpolished or buffed to remove barrier layer materials, remove surfacedefects from dielectric materials, or improve planarity of the polishingprocess using the conductive polishing article. An example of a suitablebuffing process and composition is disclosed in co-pending U.S. patentapplication Ser. No. 09/569,968, filed on May 11, 2000, and incorporatedherein by reference in its entirety.

Polishing Article Materials

The polishing articles described herein may be formed from conductivematerials that may comprise a conductive polishing material or maycomprise a conductive element disposed in a dielectric or conductivepolishing material. In one embodiment, a conductive polishing materialmay include conductive fibers, conductive fillers, or combinationsthereof. The conductive fibers, conductive fillers, or combinationsthereof may be dispersed in a polymeric material.

The conductive fibers may comprise conductive or dielectric materials,such as dielectric or conductive polymers or carbon-based materials, atleast partially coated or covered with a conductive material including ametal, a carbon-based material, a conductive ceramic material, aconductive alloy, or combinations thereof. The conductive fibers may bein the form of fibers or filaments, a conductive fabric or cloth, one ormore loops, coils, or rings of conductive fibers. Multiple layers ofconductive materials, for example, multiple layers of conductive clothor fabric, may be used to form the conductive polishing material.

The conductive fibers include dielectric or conductive fiber materialscoated with a conductive material. Dielectric polymeric materials may beused as fiber materials. Examples of suitable dielectric fiber materialsinclude polymeric materials, such as polyamides, polyimides, nylonpolymer, polyurethane, polyester, polypropylene, polyethylene,polystyrene, polycarbonate, diene containing polymers, such as AES(polyacrylontrile ethylene styrene), acrylic polymers, or combinationsthereof. The invention also contemplates the use of organic or inorganicmaterials that may be used as fibers described herein.

The conductive fiber material may comprise intrinsically conductivepolymeric materials including polyacetylene, polyethylenedioxythiophene(PEDT), which is commercially available under the trade name Baytron™,polyaniline, polypyrrole, polythiophene, carbon-based fibers, orcombinations thereof. Another example of a conductive polymer ispolymer-noble metal hybrid materials. Polymer-noble metal hybridmaterials are generally chemically inert with a surrounding electrolyte,such as those with noble metals that are resistant to oxidation. Anexample of a polymer-noble metal hybrid material is a platinum-polymerhybrid material. Examples of conductive polishing materials, includingconductive fibers, are more fully described in co-pending U.S. patentapplication Ser. No. 10/033,732, filed on Dec. 27, 2001, entitled,“Conductive Polishing Article For Electrochemical Mechanical Polishing”,which is incorporated herein by reference in its entirety. The inventionalso contemplates the use of organic or inorganic materials that may beused as fibers described herein.

The fiber material may be solid or hollow in nature. The fiber length isin the range between about 1 μm and about 1000 mm with a diameterbetween about 0.1 μm and about 1 mm. In one aspect, the diameter offiber may be between about 5 μm to about 200 μm with an aspect ratio oflength to diameter of about 5 or greater, such as about 10 or greater,for conductive polymer composites and foams, such as conductive fibersdisposed in polyurethane. The cross-sectional area of the fiber may becircular, elliptical, star-patterned, “snow flaked”, or of any othershape of manufactured dielectric or conductive fibers. High aspect ratiofibers having a length between about 5 mm and about 1000 mm in lengthand between about 5 μm and about 1000 μm in diameter may be used forforming meshes, loops, fabrics or cloths, of the conductive fibers. Thefibers may also have an elasticity modulus in the range between about10⁴ psi and about 10⁸ psi. However, the invention contemplates anyelastic modulus necessary to provide for compliant, elastic fibers inthe polishing articles and processes described herein.

Conductive material disposed on the conductive or dielectric fibermaterial generally include conductive inorganic compounds, such as ametal, a metal alloy, a carbon-based material, a conductive ceramicmaterial, a metal inorganic compound, or combinations thereof. Examplesof metal that may be used for the conductive material coatings hereininclude noble metals, tin, lead, copper, nickel, cobalt, andcombinations thereof. Noble metals include gold, platinum, palladium,iridium, rhenium, rhodium, rhenium, ruthenium, osmium, and combinationsthereof, of which gold and platinum are preferred. The invention alsocontemplates the use of other metals for the conductive materialcoatings than those illustrated herein. Carbon-based material includescarbon black, graphite, and carbon particles capable of being affixed tothe fiber surface. Examples of ceramic materials include niobium carbide(NbC), zirconium carbide (ZrC), tantalum carbide (TaC), titanium carbide(TiC), tungsten carbide (WC), and combinations thereof. The inventionalso contemplates the use of other metals, other carbon-based materials,and other ceramic materials for the conductive material coatings thanthose illustrated herein. Metal inorganic compounds include, forexample, copper sulfide or danjenite, Cu₉S₅, disposed on polymericfibers, such as acrylic or nylon fibers. The danjenite coated fibers arecommercially available under the tradename Thunderon® from Nihon SanmoDyeing Co., Ltd, of Japan. The Thunderon® fibers typically have acoating of danjenite, Cu₉S₅, between about 0.03 μm and about 0.1 μm andhave been observed to have conductivities of about 40 Ω/cm. Theconductive coating may be disposed directly on the fiber by plating,coating, physical vapor deposition, chemical deposition, binding, orbonding of the conductive materials. Additionally, a nucleation, orseed, layer of a conductive material, for example, copper, cobalt ornickel, may be used to improve adhesion between the conductive materialand the fiber material. The conductive material may be disposed onindividual dielectric or conductive fibers of variable lengths as wellas on shaped loops, foams, and cloths or fabrics made out of thedielectric or conductive fiber material.

An example of a suitable conductive fiber is a polyethylene fiber coatedwith gold. Additional examples of the conductive fibers include acrylicfibers plated with gold and nylon fibers coated with rhodium. An exampleof a conductive fiber using a nucleation material is a nylon fibercoated with a copper seed layer and a gold layer disposed on the copperlayer.

The conductive fillers may include carbon based materials or conductiveparticles and fibers. Examples of conductive carbon-based materialsinclude carbon powder, carbon fibers, carbon nanotubes, carbon nanofoam,carbon aerogels, graphite, and combinations thereof. Examples ofconductive particles or fibers include intrinsically conductivepolymers, dielectric or conductive particles coated with a conductivematerial, dielectric filler materials coated in conductive materials,conductive inorganic particles including metal particles such as gold,platinum, tin, lead and other metal or metal alloy particles, conductiveceramic particle, and combinations thereof. The conductive fillers maybe partially or completely coated with a metal, such as a noble metal, acarbon-based material, conductive ceramic material, a metal inorganiccompound, or combinations thereof, as described herein. An example of afiller material is a carbon fiber or graphite coated with copper ornickel. Conductive fillers may be spherical, elliptical, longitudinalwith certain aspect ratio, such as 2 or greater, or of any other shapeof manufactured fillers. Filler materials are broadly defined herein asmaterials that may be disposed in a second material to alter, thephysical, chemical, or electrical properties of the second material. Assuch, filler materials may also include dielectric or conductive fibermaterial partially or completely coated in a conductive metal orconductive polymers as described herein. The fillers of dielectric orconductive fiber material partially or completely coated in a conductivemetal or conductive polymers may also be complete fibers or pieces offibers.

The conductive materials are used to coat both dielectric and conductivefibers and fillers to provide a desired level of conductivity forforming the conductive polishing material. Generally, the coating ofconductive material is deposited on the fiber and/or filler material toa thickness between about 0.01 μm and about 50 μm, such as between about0.02 μm and about 10 μm. The coating typically results in fibers orfillers having resistivities less than about 100 Ω-cm, such as betweenabout 0.001 Ω-cm and about 32 Ω-cm. The invention contemplates thatresistivities are dependent on the materials of both the fiber or fillerand the coating used, and may exhibit resistivities of the conductivematerial coating, for example, platinum, which has a resistivity 9.81μΩ-cm at 0° C. An example of a suitable conductive fiber includes anylon fiber coated with about 0.1 μm copper, nickel, or cobalt, andabout 2 μm of gold disposed on the copper, nickel, or cobalt layer, witha total diameter of the fiber between about 30 μm and about 90 μm.

The conductive polishing material may include a combination of theconductive or dielectric fibers material at least partially coated orcovered with an additional conductive material and conductive fillersfor achieving a desired electrical conductivity or other polishingarticle properties. An example of a combination is the used of goldcoated nylon fibers and graphite as the conductive material comprisingat least a portion of a conductive polishing material.

The conductive fiber material, the conductive filler material, orcombinations thereof, may be dispersed in a binder material or form acomposite conductive polishing material. One form of binder material isa conventional polishing material. Conventional polishing materials aregenerally dielectric materials such as dielectric polymeric materials.Examples of dielectric polymeric polishing materials includepolyurethane and polyurethane mixed with fillers, polycarbonate,polyphenylene sulfide (PPS), polytetrafluoroethylene polymers,polystyrene, ethylene-propylene-diene-methylene (EPDM), or combinationsthereof, and other polishing materials used in polishing substratesurfaces. The conventional polishing material may also include feltfibers impregnated in urethane or be in a foamed state. The inventioncontemplates that any conventional polishing material may be used as abinder material (also known as a matrix) with the conductive fibers andfillers described herein.

Additives may be added to the binder material to assist the dispersionof conductive fibers, conductive fillers or combinations thereof, in thepolymer materials. Additives may be used to improve the mechanical,thermal, and electrical properties of the polishing material formed fromthe fibers and/or fillers and the binder material. Additives includecross-linkers for improving polymer cross-linking and dispersants fordispersing conductive fibers or conductive fillers more uniformly in thebinder material. Examples of cross-linkers include amino compounds,silane crosslinkers, polyisocyanate compounds, and combinations thereof.Examples of dispersants include N-substituted long-chain alkenylsuccinimides, amine salts of high-molecular-weight organic acids,co-polymers of methacrylic or acrylic acid derivatives containing polargroups such as amines, amides, imines, imides, hydroxyl, ether,Ethylene-propylene copolymers containing polar groups such as amines,amides, imines, imides, hydroxyl, ether. In addition sulfur containingcompounds, such as thioglycolic acid and related esters have beenobserved as effective dispersers for gold coated fibers and fillers inbinder materials. The invention contemplates that the amount and typesof additives will vary for the fiber or filler material as well as thebinder material used, and the above examples are illustrative and shouldnot be construed or interpreted as limiting the scope of the invention.

Further, a mesh of the conductive fiber and/or filler material may beformed in the binder material by providing sufficient amounts ofconductive fiber and/or conductive filler material to form a physicallycontinuous or electrically continuous medium or phase in the bindermaterial. The conductive fibers and/or conductive fillers generallycomprise between about 2 wt. % and about 85 wt. %, such as between about5 wt. % and about 60 wt. %, of the polishing material when combined witha polymeric binder material.

An interwoven fabric or cloth of the fiber material coated with aconductive material, and optionally, a conductive filler, may bedisposed in the binder. The fiber material coated with a conductivematerial may be interwoven to form a yarn. The yarns may be broughttogether to make a conductive mesh with the help of adhesives orcoatings. The yarn may be disposed as a conductive element in apolishing pad material or may be woven into a cloth or fabric.

Alternatively, the conductive fibers and/or fillers may be combined witha bonding agent to form a composite conductive polishing material.Examples of suitable bonding agents include epoxies, silicones,urethanes, polyimides, a polyamide, a fluoropolymer, fluorinatedderivatives thereof, or combinations thereof. Additional conductivematerial, such as conductive polymers, additional conductive fillers, orcombinations thereof, may be used with the bonding agent for achievingdesired electrical conductivity or other polishing article properties.The conductive fibers and/or fillers may include between about 2 wt. %and about 85 wt. %, such as between about 5 wt. % and about 60 wt. %, ofthe composite conductive polishing material.

The conductive fiber and/or filler material may be used to formconductive polishing materials or articles having bulk or surfaceresistivity of about 50 Ω-cm or less, such as a resistivity of about 3Ω-cm or less. In one aspect of the polishing article, the polishingarticle or polishing surface of the polishing article has a resistivityof about 1 Ω-cm or less. Generally, the conductive polishing material orthe composite of the conductive polishing material and conventionalpolishing material are provided to produce a conductive polishingarticle having a bulk resistivity or a bulk surface resistivity of about50 Ω-cm or less. An example of a composite of the conductive polishingmaterial and conventional polishing material includes gold or carboncoated fibers which exhibit resistivities of 1 Ω-cm or less, disposed ina conventional polishing material of polyurethane in sufficient amountsto provide a polishing article having a bulk resistivity of about 10Ω-cm or less.

The conductive polishing materials formed from the conductive fibersand/or fillers described herein generally have mechanical propertiesthat do not degrade under sustained electric fields and are resistant todegradation in acidic or basic electrolytes. The conductive material andany binder material used are combined to have equivalent mechanicalproperties, if applicable, of conventional polishing materials used in aconventional polishing article. For example, the conductive polishingmaterial, either alone or in combination with a binder material, has ahardness of about 100 or less on the Shore D Hardness scale forpolymeric materials as described by the American Society for Testing andMaterials (ASTM), headquartered in Philadelphia, Pa. In one aspect, theconductive material has a hardness of about 80 or less on the Shore DHardness scale for polymeric materials. The conductive polishing portion310 generally includes a surface roughness of about 500 microns or less.The properties of the polishing pad are generally designed to reduce orminimize scratching of the substrate surfaces during mechanicalpolishing and when applying a bias to the substrate surface.

Polishing Article Structures

In one aspect, the polishing article is composed of a single layer ofconductive polishing material described herein disposed on a support. Inanother aspect, the polishing article may comprise a plurality ofmaterial layers including at least one conductive material on thesubstrate surface or providing for a conductive surface for contacting asubstrate and at least one article support portion or sub-pad.

FIG. 3 is a partial cross-sectional view of one embodiment of apolishing article 205. Polishing article 205 illustrated in FIG. 3comprises a composite polishing article having a conductive polishingportion 310 for polishing a substrate surface and an article support, orsub-pad, portion 320.

The conductive polishing portion 310 may comprise a conductive polishingmaterial including the conductive fibers and/or conductive fillers asdescribed herein. For example, the conductive polishing portion 310 mayinclude a conductive material comprising conductive fibers and/orconductive fillers dispersed in a polymeric material. The conductivefillers may be disposed in a polymer binder. The conductive fillers mayinclude soft conductive materials disposed in a polymer binder. Softconductive materials generally have a hardness and modulus less than orequal to about that of copper. Examples of soft conductive materialsinclude gold, tin, palladium, palladium-tin alloys, platinum, and lead,among other conductive metals, alloys and ceramic composites softer thancopper. The invention contemplates the use of other conductive fillersharder than copper if their size is small enough not to scratchpolishing substrate. Further, the conductive polishing portion mayinclude one or more loops, coils, or rings of conductive fibers, orconductive fibers interwoven to form a conductive fabric or cloth. Theconductive polishing portion 310 may also be comprised of multiplelayers of conductive materials, for example, multiple layers ofconductive cloth or fabric.

One example of the conductive polishing portion 310 includes gold coatednylon fibers and graphite particles disposed in polyurethane. Anotherexample includes graphite particles and/or carbon fibers disposed inpolyurethane or silicone. Another example includes gold or tin particlesdispersed in polyurethane matrix.

In another embodiment, the conductive polishing portion 310 may haveabrasive particles 360 disposed therein. At least some of the abrasiveparticles 360 are exposed on an upper polishing surface 370 of theconductive polishing portion 310. The abrasive particles 360 generallyare configured to remove the passivation layer of the metal surface ofthe substrate being polished, thereby exposing the underlying metal tothe electrolyte and electrochemical activity, thereby enhancing the rateof polishing during processing. Examples of abrasive particles 360include ceramic, inorganic, organic, or polymer particle strong enoughto break the passivation layer formed at the metal surface. Polymerparticles may be solid or spongy to tailor the wear rate of thepolishing portion 310.

The article support portion 320 generally has the same or smallerdiameter or width of the conductive polishing portion 310. However, theinvention contemplates the article support portion 320 having a greaterwidth or diameter than the conductive polishing portion 310. While thefigures herein illustrate a circular conductive polishing portion 310and article support portion 320, the invention contemplates that theconductive polishing portion 310, the article support portion 320, orboth may have different shapes such as rectangular surfaces orelliptical surfaces. The invention further contemplates that theconductive polishing portion 310, the article support portion 320, orboth, may form a linear web or belt of material.

The article support portion 320 may comprise inert materials in thepolishing process and are resistant to being consumed or damaged duringECMP. For example, the article support portion may be comprised of aconventional polishing materials, including polymeric materials, forexample, polyurethane and polyurethane mixed with fillers,polycarbonate, polyphenylene sulfide (PPS),ethylene-propylene-diene-methylene (EPDM), polytetrafluoroethylenepolymers, or combinations thereof, and other polishing materials used inpolishing substrate surfaces. The article support portion 320 may be aconventional soft material, such as compressed felt fibers impregnatedwith urethane, for absorbing some of the pressure applied between thepolishing article 205 and the carrier head 130 during processing. Thesoft material may have a Shore A hardness between about 20 and about 90.

Alternatively, the article support portion 320 may be made from aconductive material compatible with surrounding electrolyte that wouldnot detrimentally affect polishing including conductive noble metals ora conductive polymer, to provide electrical conduction across thepolishing article. Examples of noble metals include gold, platinum,palladium, iridium, rhenium, rhodium, rhenium, ruthenium, osmium, andcombinations thereof, of which gold and platinum are preferred.Materials that are reactive with the surrounding electrolyte, such ascopper, may be used if such materials are isolated from the surroundingelectrolyte by an inert material, such as a conventional polishingmaterial or a noble metal.

When the article support portion 320 is conductive, the article supportportion 320 may have a greater conductivity, i.e., lower resistivity,than the conductive polishing portion 310. For example, the conductivepolishing portion 310 may have a resistivity of about 1.0 Ω-cm or lessas compared to an article support portion 320 comprising platinum, whichhas a resistivity 9.81 μΩ-cm at 0° C. A conductive article supportportion 320 may provide for uniform bias or current to minimizeconductive resistance along the surface of the article, for example, theradius of the article, during polishing for uniform anodic dissolutionacross the substrate surface. A conductive article support portion 320may be coupled to a power source for transferring power to theconductive polishing portion 310.

Generally, the conductive polishing portion 310 is adhered to thearticle support portion 320 by a conventional adhesive suitable for usewith polishing materials and in polishing processes. The inventioncontemplates the use of other means to attach the conductive polishingportion 310 onto the article support portion 320 such as compressionmolding and lamination. The adhesive may be conductive or dielectricdepending on the requirements of the process or the desires of themanufacturer. The article support portion 320 may be affixed to asupport, such as disc 206, by an adhesive or mechanical clamp.Alternatively, if polishing article 205 only includes a conductivepolishing portion 310, the conductive polishing portion may be affixedto a support, such as disc 206, by an adhesive or mechanical clamp

The conductive polishing portion 310 and the article support portion 320of the polishing article 205 are generally permeable to the electrolyte.A plurality of perforations may be formed, respectively, in theconductive polishing portion 310 and the article support portion 320 tofacilitate fluid flow therethrough. The plurality of perforations allowselectrolyte to flow through and contact the surface during processing.The perforations may be inherently formed during manufacturing, such asbetween weaves in a conductive fabric or cloth, or may be formed andpatterned through the materials by mechanical means. The perforationsmay be formed partially or completely through each layer of thepolishing article 205. The perforations of the conductive polishingportion 310 and the perforations of the article support portion 320 maybe aligned to facilitate fluid flow therethrough.

Examples of perforations 350 formed in the polishing article 205 mayinclude apertures in the polishing article having a diameter betweenabout 0.02 inches (0.5 millimeters) and about 0.4 inches (10 mm). Thethickness of the polishing article 205 may be between about 0.1 mm andabout 5 mm. For example, perforations may be spaced between about 0.1inches and about 1 inch from one another.

The polishing article 205 may have a perforation density between about20% and about 80% of the polishing article in order to providesufficient mass flow of electrolyte across the polishing articlesurface. However, the invention contemplates perforation densities belowor above the perforation density described herein that may be used tocontrol fluid flow therethrough. In one example, a perforation densityof about 50% has been observed to provide sufficient electrolyte flow tofacilitate uniform anodic dissolution from the substrate surface.Perforation density is broadly described herein as the volume ofpolishing article that the perforations comprise. The perforationdensity includes the aggregate number and diameter or size of theperforations, of the surface or body of the polishing article whenperforations are formed in the polishing article 205.

The perforation size and density is selected to provide uniformdistribution of electrolyte through the polishing article 205 to asubstrate surface. Generally, the perforation size, perforation density,and organization of the perforations of both the conductive polishingportion 310 and the article support portion 320 are configured andaligned to each other to provide for sufficient mass flow of electrolytethrough the conductive polishing portion 310 and the article supportportion 320 to the substrate surface.

Grooves may be disposed in the polishing article 205 to promoteelectrolyte flow across the polishing article 205 to provide effectiveor uniform electrolyte flow with the substrate surface for anodicdissolution or electroplating processes. The grooves may be partiallyformed in a single layer or through multiple layers. The inventioncontemplates grooves being formed in the upper layer or polishingsurface that contacts the substrate surface. To provide increased orcontrolled electrolyte flow to the surface of the polishing article, aportion or plurality of the perforations may interconnect with thegrooves. Alternatively, the all or none of the perforations mayinterconnect with the grooves disposed in the polishing article 205.

Examples of grooves used to facilitate electrolyte flow include lineargrooves, arcuate grooves, annular concentric grooves, radial grooves,and helical grooves among others. The grooves formed in the article 205may have a cross-section that is square, circular, semi-circular, or anyother shape that may facilitate fluid flow across the surface of thepolishing article. The grooves may intersect each other. The grooves maybe configured into patterns, such as an intersecting X-Y patterndisposed on the polishing surface or an intersecting triangular patternformed on the polishing surface, or combinations thereof, to improveelectrolyte flow over the surface of the substrate.

The grooves may be spaced between about 30 mils and about 300 mils apartfrom one another. Generally, grooves formed in the polishing articlehave a width between about 5 mils and about 30 mils, but may vary insize as required for polishing. An example of a groove pattern includesgrooves of about 10 mils wide spaced about 60 mils apart from oneanother. Any suitable groove configuration, size, diameter,cross-sectional shape, or spacing may be used to provide the desiredflow of electrolyte. Additional cross sections and groove configurationsare more fully described in co-pending U.S. Patent ProvisionalApplication Ser. No. 60/328,434, filed on Oct. 11, 2001, entitled“Method And Apparatus For Polishing Substrates”, which is incorporatedherein by reference in its entirety.

Electrolyte transport to the surface of the substrate may be enhanced byintersecting some of the perforations with the grooves to allowelectrolyte to enter through one set of perforation, be evenlydistributed around the substrate surface by the grooves, used inprocessing a substrate, and then processing electrolyte is refreshed byadditional electrolyte flowing through the perforations. An example of apad perforation and grooving is more fully described in U.S. patentapplication Ser. No. 10/026,854, filed Dec. 20, 2001, which isincorporated by reference in its entirety.

Examples of polishing articles having perforations and grooves are asfollows. FIG. 4 is a top plan view of one embodiment of a groovedpolishing article. A round pad 440 of the polishing article 205 is shownhaving a plurality of perforations 446 of a sufficient size andorganization to allow the flow of electrolyte to the substrate surface.The perforations 446 can be spaced between about 0.1 inches and about 1inch from one another. The perforations may be circular perforationshaving a diameter of between about 0.02 inches (0.5 millimeters) andabout 0.4 inches (10 mm). Further the number and shape of theperforations may vary depending upon the apparatus, processingparameters, and ECMP compositions being used.

Grooves 442 are formed in the polishing surface 448 of the polishingarticle 205 therein to assist transport of fresh electrolyte from thebulk solution from basin 202 to the gap between the substrate and thepolishing article. The grooves 442 may have various patterns, includinga groove pattern of substantially circular concentric grooves on thepolishing surface 448 as shown in FIG. 4, an X-Y pattern as shown inFIG. 5 and a triangular pattern as shown in FIG. 6.

FIG. 5 is a top plan view of another embodiment of a polishing padhaving grooves 542 disposed in an X-Y pattern on the polishing portion548 of a polishing pad 540. Perforations 546 may be disposed at theintersections of the vertically and horizontally disposed grooves, andmay also be disposed on a vertical groove, a horizontal groove, ordisposed in the polishing article 548 outside of the grooves 542. Theperforations 546 and grooves 542 are disposed in the inner diameter 544of the polishing article and the outer diameter 550 of the polishing pad540 may be free of perforations and grooves and perforations.

FIG. 6 is another embodiment of patterned polishing article 640. In thisembodiment, grooves may be disposed in an X-Y pattern with diagonallydisposed grooves 645 intersecting the X-Y patterned grooves 642. Thediagonal grooves 645 may be disposed at an angle from any of the X-Ygrooves 642, for example, between about 300 and about 60° from any ofthe X-Y grooves 642. Perforations 646 may be disposed at theintersections of the X-Y grooves 642, the intersections of the X-Ygrooves 642 and diagonal grooves 645, along any of the grooves 642 and645, or disposed in the polishing article 648 outside of the grooves 642and 645. The perforations 646 and grooves 642 are disposed in the innerdiameter 644 of the polishing article and the outer diameter 650 of thepolishing pad 640 may be free of perforations and grooves.

Additional examples of groove patterns, such as spiraling grooves,serpentine grooves, and turbine grooves, are more fully described inco-pending U.S. Patent Provisional Application Ser. No. 60/328,434,filed on Oct. 11, 2001, entitled “Method And Apparatus For PolishingSubstrates”, which is incorporated herein by reference in its entirety.

In addition to the perforations and grooves in the polishing article205, the conductive polishing portion 310 may be embossed to includesurface texture. The embossment may improve the transportation ofelectrolytes, removed substrate materials, by products, and particles.The embossment may also reduce scratches to polishing substrate andmodify the friction between polishing substrate and the polishingarticle 205. The embossed surface textures distribute uniformly acrossthe conductive polishing portion 310. Embossed surface textures mayinclude structures such as pyramids, islands, crosses along withcircular, rectangular and square shapes, among other geometric forms.The invention contemplates other texture structures embossed onconductive polishing portion 310. The embossed surface may cover 5 to 95percent surface area of the conductive polishing portion 310, such asbetween 15 percent and 90 percent surface area of the conductivepolishing portion 310.

Conductive Polishing Surfaces

FIG. 7A is a top sectional view of one embodiment of a conductive clothor fabric 700 that may be used to form a conductive polishing portion310 of the polishing article 205. The conductive cloth of fabric iscomposed of interwoven fibers 710 coated with a conductive material asdescribed herein.

In one embodiment, a weave or basket-weave pattern of the interwovenfibers 710 in the vertical 720 and horizontal 730 (shown in the plane ofFIG. 7A) directions is illustrated in FIG. 7A. The inventioncontemplates other form of fabrics, such as yarns, or differentinterwoven, web, or mesh patterns to form the conductive cloth or fabric700. In one aspect, the fibers 710 are interwoven to provide passages740 in the fabric 700. The passages 740 allow electrolyte or fluid flow,including ions and electrolyte components, through the fabric 700. Theconductive fabric 700 may be disposed in a polymeric binder, such aspolyurethane. Conductive fillers may also be disposed in such apolymeric binder.

FIG. 7B is a partial cross-sectional view of the conductive cloth orfabric 700 disposed on the article support portion 320 of the article205. The conductive cloth or fabric 700 may be disposed as one or morecontinuous layers over the article support portion 320 including anyperforations 350 formed in the article support portion 320. The cloth orfabric 700 may be secured to the article support portion 320 by anadhesive. The fabric 700 is adapted to allow electrolyte flow throughthe fibers, weaves, or passages formed in the cloth or fabric 700 whenimmersed in an electrolyte solution. Optionally an interposed layer maybe included between the cloth or fabric 700 and article support portion320. The interposed layer is permeable or includes perforations alignedwith the perforations 350 for the electrolyte flow through the article205.

Alternatively, the fabric 700 may also be perforated to increaseelectrolyte flow therethrough if the passages 740 are determined to notbe sufficient to allow effective flow of electrolyte through the fabric700, i.e., metal ions cannot diffuse through. The fabric 700 istypically adapted or perorated to allow flow rates of electrolytesolutions of up to about 20 gallons per minute.

FIG. 7C is a partial cross-sectional view of the cloth or fabric 700 maybe patterned with perforations 750 to match the pattern of perforations350 in the article support portion 320. Alternatively, some or all ofthe perforations 750 of the conductive cloth or fabric 700 may not bealigned with the perforations 350 of the article support portion 320.Aligning or non-aligning of perforations allow the operator ormanufacturer to control the volume or flow rate of electrolyte throughthe polishing article to contact the substrate surface.

An example of the fabric 700 is an interwoven basket weave of betweenabout 8 and about 10 fibers wide with the fiber comprising a nylon fibercoated with gold. An example of the fiber is a nylon fiber, about 0.1 μmof cobalt, copper, or nickel material disposed on the nylon fiber, andabout 2 μm of gold disposed on the cobalt, copper, or nickel material.

Alternatively, a conductive mesh may be used in place of the conductivecloth or fabric 700. The conductive mesh may comprises conductivefibers, conductive fillers, or at least a portion of a conductive cloth700 disposed in or coated with a conductive binder. The conductivebinder may comprise a non-metallic conductive polymer or a composite ofconductive material disposed in a polymeric compound. A mixture of aconductive filler, such as graphite powder, graphite flakes, graphitefibers, carbon fibers, carbon powder, carbon black, metallic particlesor fibers coated in a conductive material, and a polymeric material,such as polyurethane, may be used to form the conductive binder. Thefibers coated with a conductive material as described herein may be usedas a conductive filler for use in the conductive binders. For example,carbon fibers or gold-coated nylon fibers may be used to form aconductive binder.

The conductive binder may also include additives if needed to assist thedispersion of conductive fillers and/or fibers, improve adhesion betweenpolymer and fillers and/or fibers, and improve adhesion between theconductive foil and the conductive binder, as well as to improve ofmechanical, thermal and electrical properties of conductive binder.Examples of additives to improve adhesion include epoxies, silicones,urethanes, polyimides, or combinations thereof for improved adhesion.

The composition of the conductive fillers and/or fibers and polymericmaterial may be adapted to provide specific properties, such asconductivity, abrasion properties, durability factors. For exampleconductive binders comprising between about 2 wt. % and about 85 wt. %of conductive fillers may be used with the articles and processesdescribed herein. Examples of materials that may be used as conductivefillers and conductive binders are more fully described in U.S. patentapplication Ser. No. 10/033,732, filed Dec. 27, 2001, which isincorporated herein by reference in its entirety.

The conductive binder may have a thickness of between about 1 micronsand 10 millimeters, such as between about 10 microns and about 1millimeter thick. Multiple layers of conductive binders may be appliedto the conductive mesh. The conductive mesh may be used in the samemanner as the conductive cloth or fabric 700 as shown in FIGS. 7B and7C. The conductive binder may be applied in multiple layers over theconductive mesh. In one aspect, the conductive binder is applied to theconductive mesh after the mesh has been perforated to protect theportion of the mesh exposed from the perforation process.

Additionally, a conductive primer may be disposed on the conductive meshbefore application of a conductive binder to improve adhesion of theconductive binder to the conductive mesh. The conductive primer may bemade of similar material to the conductive binder fibers with acomposition modified to produce properties having a greaterintermaterial adhesion than the conductive binder. Suitable conductiveprimer materials may have resistivities below about 100 Ω-cm, such asbetween 0.001 Ω-cm and about 32 Ω-cm.

Alternatively, a conductive foil may be used in place of the conductivecloth or fabric 700 as shown in FIG. 7D. The conductive foil generallyincludes a metal foil 780 disposed in or coated with a conductive binder790 on the support layer 320. Examples of material forming metal foilsinclude metal coated fabrics, conductive metals such as copper, nickel,and cobalt, and noble metals, such as gold, platinum, palladium,iridium, rhenium, rhodium, rhenium, ruthenium, osmium, tin, lead, andcombinations thereof, of which gold, tin and platinum are preferred. Theconductive foil may also include a nonmetallic conductive foil sheet,such as a copper sheet, carbon fiber woven sheet foil. The conductivefoil may also include a metal coated cloth of a dielectric or conductivematerial, such as copper, nickel, tin or gold coating a cloth of nylonfibers. The conductive foil may also comprise a fabric of conductive ordielectric material coated with a conductive binder material asdescribed herein. The conductive foil may also comprise a wire frame,screen or mesh of interconnecting conductive metal wires or strips, suchas copper wire, which may be coated with a conductive binder material asdescribed herein. The invention contemplates the use of other materialin forming the metal foil described herein.

A conductive binder 790 as described herein may encapsulate the metalfoil 780, which allows the metal foil 780 to be conductive metals thatare observed to react with the surrounding electrolyte, such as copper.The conductive foil may be perforated with a plurality of perforation750 as described herein. While not shown, the conductive foil may becoupled to a conductive wire to power supply to bias the polishingsurface.

The conductive binder 790 may be as described for the conductive mesh orfabric 700 and may be applied in multiple layers over the metal foil780. In one aspect, the conductive binder 790 is applied to the metalfoil 780 after the metal foil 780 has been perforated to protect theportion of the metal foil 780 exposed from the perforation process.

The conductive binder described herein may be disposed onto conductivefabric 700, foil 780, or mesh by casting liquid state adhesive or binderonto the fabric 700, foil 780 or mesh. The binder is then solidified onthe fabric, foil or mesh after drying and curing. Other suitableprocessing methods including injection mold, compression mold,lamination, autoclave, extrusion, or combinations thereof may be used toencapsulate the conductive fabric, mesh, or foil. Both thermoplastic andthermosetting binders may be used for this application.

Adhesion between the conductive binder and the metal foil components ofthe conductive foil may be enhanced by perforating the metal foil with aplurality of perforations having a diameter or width between about 0.1μm and about 1 mm or by applying a conductive primer between the metalfoil and the conductive binder. The conductive primer may be of the samematerial as the conductive primer for the mesh described herein.

FIG. 7E is a sectional view of another embodiment of a conductive clothor fabric 798 that may be used to form a lower layer 792 of a conductivepolishing portion 310 of the polishing article 205. The conductive clothof fabric may be comprised of interwoven or alternatively non-wovenfibers 710. The fibers 710 may be formed from or coated with aconductive material as described above. Examples of non-woven fibersinclude spun-bond or melt blown polymers among other non-woven fabrics.

The conductive polishing portion 310 includes an upper layer 794comprised of a conductive material. The upper layer 794 includes apolishing surface 796 disposed opposite the lower layer 792. The upperlayer 794 may have sufficient thickness to smooth out the irregularitiesof the underlying lower layer 792, thereby providing a generally flatand planar polishing surface 796 for contacting the substrate duringprocessing. In one embodiment, the polishing surface 796 has a thicknessvariation of less than or equal to about ±1 mm and a surface roughnessof less than or equal to about 500 micron meter.

The upper layer 794 may be comprised of any conductive material. In oneembodiment, the upper layer 794 is formed from a soft material such asgold, tin, palladium, palladium-tin alloys, platinum, or lead, amongother conductive metals, alloys and ceramic composites softer thancopper. The upper layer 794 may optionally include abrasive materialdisposed therein as described above to assist in removing thepassivation layer disposed on the metal surface of the substrate beingpolished.

Alternatively, the upper layer 794 may be comprised of a non-conductivematerial that substantially covers the conductive polishing portion 310yet leaves at least a portion of the conductive polishing portionexposed such that the conductive polishing portion 310 may beelectrically coupled to a substrate being polished on the upper layer794. In such a configuration, the upper layer 794 assists in reducingscratching and prevents the conductive portion 310 from entering anyexposed features during polishing. A non-conductive upper layer 794 mayinclude a plurality of perforations that allow the conductive polishingportion 310 to remain exposed.

FIG. 7F is another embodiment of a polishing article 205 having a window702 formed therein. The window 702 is configured to allow a sensor 704positioned below the polishing article 205 to sense a metric indicativeof polishing performance. For example, the sensor 704 may be an eddycurrent sensor or an interferometer, among other sensors. In oneembodiment, the sensor an interferometer capable of generating acollimated light beam, which during processing, is directed at andimpinges on a side of the substrate 114 that is being polished. Theinterference between reflected signals is indicative of the thickness ofthe layer of material being polished. One sensor that may be utilized toadvantage is described in U.S. Pat. No. 5,893,796, issued Apr. 13, 1999,to Birang, et al., which is hereby incorporated by reference in itsentirety.

The window 702 includes a fluid barrier 706 that substantially preventsprocessing fluids from reaching the area of the disc 206 housing thesensor 704. The fluid barrier 706 is generally selected be transmissive(e.g., to have minimal or no effect or interference) to the signalspassing therethrough. The fluid barrier 706 may be a separate element,such as a block of polyurethane coupled to the polishing article 205within the window 702, or be one or more of the layers comprising thepolishing article 205, for example, a sheet of mylar underlying theconductive portion 310 or the article support, or sub-pad, portion 320.Alternatively, fluid barrier 706 may be disposed in the layers disposedbetween the polishing article 205 and the disc 206, such as theelectrode 204 or other layer. In yet another alternative configuration,the fluid barrier 706 may be disposed in a passage 708 aligned with thewindow 702 in which the sensor 704 resides. In embodiments wherein theconductive portion 310 comprises multiply layers, for example, an upperlayer 794 and a lower layer 792, the transparent material 706 may bedisposed in at least one layer comprising the conductive portion 310 asshown in FIG. 7F. It is contemplated that other configurations ofconductive polishing articles, including those embodiments describedherein along with other configurations, may be adapted to include awindow.

Conductive Elements in Polishing Surfaces

In another aspect, the conductive fibers and fillers described hereinmay be used to form distinct conductive elements disposed in a polishingmaterial to form the conductive polishing article 205 of the invention.The polishing material may be a conventional polishing material or aconductive polishing material, for example, a conductive composite ofconductive fillers or fibers disposed in the polymer as describedherein. The surface of the conductive elements may form a plane with thesurface of the polishing article or may extend above a plane of thesurface of the polishing article. Conductive elements may extend up toabout 5 millimeters above the surface of the polishing article.

While the following illustrate the use of conductive elements having aspecific structure and arrangement in the polishing material, theinvention contemplates that individual conductive fibers and fillers,and materials made therefrom, such as fabrics, may also be consideredconductive elements. Further, while not shown, the following polishingarticle descriptions may include polishing articles having perforationand grooving patterns described herein and shown in FIGS. 4-6, withconfigurations to the patterns to incorporate the conductive elementsdescribed herein as follows.

FIGS. 8A-8B depict a top and a cross-sectional schematic view of oneembodiment of a polishing article 800 having conductive elementsdisposed therein. The polishing article 800 generally comprises a body810 having a polishing surface 820 adapted to contact the substratewhile processing. The body 810 typically comprises a dielectric orpolymeric material, such as a dielectric polymer material, for example,polyurethane.

The polishing surface 820 has one or more openings, grooves, trenches,or depressions 830 formed therein to at least partially receiveconductive elements 840. The conductive elements 840 may be generallydisposed to have a contact surface 850 co-planar or extending above aplane defined by the polishing surface 820. The contact surface 850 istypically configured, such as by having a compliant, elastic, flexible,or pressure moldable surface, to maximize electrical contact of theconductive elements 840 when contacting the substrate. During polishing,a contact pressure may be used to urge the contact surface 850 into aposition co-planar with the polishing surface 820.

The body 810 is generally made permeable to the electrolyte by aplurality of perforations 860 formed therein as described herein. Thepolishing article 800 may have a perforation density between about 20%and about 80% of the surface area of the polishing article 810 toprovide sufficient electrolyte flow to facilitate uniform anodicdissolution from the substrate surface.

The body 810 generally comprises a dielectric material such as theconventional polishing materials described herein. The depressions 830formed in the body 810 are generally configured to retain the conductiveelements 840 during processing, and accordingly may vary in shape andorientation. In the embodiment depicted in FIG. 8A, the depressions 830are grooves having a rectangular cross section disposed across thepolishing article surface and forming an interconnecting “X” or crosspattern 870 at the center of the polishing article 800. The inventioncontemplates additional cross sections, such as inverse trapezoidal androunded curvature where the groove contacts the substrate surface asdescribed herein.

Alternatively, the depressions 830 (and conductive elements 840 disposedtherein) may be disposed at irregular intervals, be orientated radially,parallel, or perpendicular, and may additionally be linear, curved,concentric, involute curves, or other cross-sectional areas.

FIG. 8C is a top schematic view of a series of individual conductiveelements 840 radially disposed in the body 810, each element 840separated physically or electrically by a spacer 875. The spacer 875 maybe a portion of dielectric polishing material or a dielectricinterconnect for the elements, such as a plastic interconnect.Alternatively, the spacer 875 may be a section of the polishing articledevoid of either the polishing material or conductive elements 840 toprovide an absence of physical connection between the conductiveelements 840. In such a separate element configuration, each conductiveelement 840 may be individually connected to a power source by aconductive path 890, such as a wire.

Referring back to FIGS. 8A and 8B, the conductive elements 840 disposedin the body 810 are generally provided to produce a bulk resistivity ora bulk surface resistivity of about 20 Ω-cm or less. In one aspect ofthe polishing article, the polishing article has a resistivity of about2 Ω-cm or less. The conductive elements 840 generally have mechanicalproperties that do not degrade under sustained electric fields and areresistant to degradation in acidic or basic electrolytes. The conductiveelements 840 are retained in the depressions 830 by press fit, clamping,adhesive, or by other methods.

In one embodiment, the conductive elements 840 are sufficientlycompliant, elastic, or flexible to maintain electrical contact betweenthe contact surface 850 and the substrate during processing. Sufficientcompliant, elastic, or flexible materials for the conductive element 840may have an analogous hardness of about 100 or less on the Shore DHardness scale compared to the polishing material. A conductive element840 having an analogous hardness of about 80 or less on the Shore DHardness scale for polymeric materials may be used. A compliantmaterial, such as flexible or bendable fibers of material, may also beused as the conductive elements 840. The conductive element 840 may bemore compliant than polishing material to avoid high local pressureintroduced by conductive element 840 during polishing.

In the embodiment depicted in FIGS. 8A and 8B, the conductive elements840 are embedded in the polishing surface 810 disposed on an articlesupport or sub-pad 815. Perforations 860 are formed through bothpolishing surface 810 and the article support 815 around conductiveelements 840.

An example of the conductive elements 840 includes dielectric orconductive fibers coated with a conductive material or conductivefillers blended with a polymeric material, such as a polymer basedadhesive, to make a conductive (and wear resistant) composite asdescribed herein. The conductive elements 840 may also compriseconductive polymeric material or other conductive materials as describedherein to improve electrical properties. For example, the conductiveelements comprise a composite of a conductive epoxy and a conductivefiber comprising a nylon fiber coated with gold, such as a nylon fibercoated with about 0.1 μm of cobalt, copper, or nickel disposed on thenylon fiber, and about 2 μm of gold disposed on the a nylon fiber, andcarbon or graphite fillers to improve the composite's conductivity,which is deposited in a body of polyurethane.

FIG. 8D is a cross-sectional schematic view of another embodiment of apolishing article 800 having conductive elements disposed therein. Theconductive elements 840 may be generally disposed to have a contactsurface co-planar or extending above a plane defined by the polishingsurface 820. The conductive elements 840 may include the conductivefabric 700, as described herein, disposed, encapsulated or wrappedaround a conductive member 845. Alternatively individual conductivefibers and/or fillers may be disposed, encapsulated, or wrapped aroundthe conductive member 845. The conductive member 845 may comprise ametal, such as a noble metal described herein, or other conductivematerials, such as copper, suitable for use in electropolishingprocesses. The conductive element 840 may also comprise a composite ofthe fabric and a binder material as described herein with the fabricforming an outer contact portion of the conductive element 840 and thebinder typically forming an inner support structure. The conductiveelement 840 may also comprise a hollow tube having a rectangularcross-sectional area with the walls of the tube formed of rigidconductive fabric 700 and a bonding agent as described herein.

A connector 890 is utilized to couple the conductive elements 840 to apower source (not shown) to electrically bias the conductive elements840 during processing. The connector 890 is generally a wire, tape orother conductor compatible with process fluids or having a covering orcoating that protects the connector 890 from the process fluids. Theconnector 890 may be coupled to the conductive elements 840 by molding,soldering, stacking, brazing, clamping, crimping, riveting, fastening,conductive adhesive or by other methods or devices. Examples ofmaterials that may be utilized in the connector 890 include insulatedcopper, graphite, titanium, platinum, gold, aluminum, stainless steel,and HASTELOY® conductive materials among other materials.

Coatings disposed around the connectors 890 may include polymers such asfluorocarbons, poly-vinyl chloride (PVC) and polyimide. In theembodiment depicted in FIG. 8A, one connector 890 is coupled to eachconductive element 840 at the perimeter of the polishing article 800.Alternatively, the connectors 890 may be disposed through the body 810of the polishing article 800. In yet another embodiment, the connector890 may be coupled to a conductive grid (not shown) disposed in thepockets and/or through the body 810 that electrically couples theconductive elements 840.

FIG. 9A depicts another embodiment of a polishing material 900. Thepolishing material 900 includes a body 902 having one or more at leastpartially conductive elements 904 disposed on a polishing surface 906.The conductive elements 904 generally comprise a plurality of fibers,strands, and/or flexible fingers that are compliant or elastic andadapted to contact a substrate surface while processing. The fibers arecomprised of an at least partially conductive material, such as a fibercomposed of a dielectric material coated with a conductive material asdescribed herein. The fibers may also be solid or hollow in nature todecrease or increase the amount of compliance or flexibility of thefibers.

In the embodiment depicted in FIG. 9A, the conductive elements 904 are aplurality of conductive sub-elements 913 coupled to a base 909. Theconductive sub-elements 913 include the at least partially electricallyconductive fibers described herein. An example of the sub-elements 913include a nylon fiber coated with gold as described herein or carbonfiber. The base 909 also comprises an electrically conductive materialand is coupled to a connector 990. The base 909 may also be coated by alayer of conductive material, such as copper, that dissolves from thepolishing pad article during polishing, which is believed to extend theprocessing duration of the conductive fibers.

The conductive elements 904 generally are disposed in a depression 908formed in the polishing surface 906. The conductive elements 904 may beorientated between 0 and 90 degrees relative to the polishing surface906. In embodiments where the conductive elements 904 are orientatedperpendicular to the polishing surface 906, the conductive elements 904may partially be disposed on the polishing surface 906.

The depressions 908 have a lower mounting portion 910 and an upper,clearance portion 912. The mounting portion 910 is configured to receivethe base 909 of the conductive elements 904, and retain the conductiveelements 904 by press fit, clamping, adhesive, or by other methods. Theclearance portion 912 is disposed where the depression 908 intersectsthe polishing surface 906. The clearance portion 912 is generally largerin cross section than the mounting portion 910 to allow the conductiveelements 904 to flex when contacting a substrate while polishing withoutbeing disposed between the substrate and the polishing surface 906.

FIG. 9B depicts another embodiment of a polishing article 900 having aconducting surface 940 and a plurality of discrete conductive elements920 formed thereon. The conductive elements 920 comprise fibers ofdielectric material coated by a conductive material are verticallydisplaced from the conducting surface 940 of the polishing article 205and are horizontally displaced from each other. The conducting elements920 of the polishing article 900 are generally orientated between 0 to90 degrees relative to a conducting surface 940 and can be inclined inany polar orientation relative to a line normal to the conductingsurface 940. The conductive elements 920 may be formed across the lengthof the polishing pads, as shown in FIG. 9B or only may be disposed inselected areas of the polishing pad. The contact height of theconductive elements 920 above the polishing surface may be up to about 5millimeters. The diameter of the material comprising the conductiveelement 920 is between about 1 mil (thousandths of an inch) and about 10mils. The height above the polishing surface and a diameter of theconductive elements 920 may vary upon the polishing process beingperformed.

The conductive elements 920 are sufficiently compliant or elastic todeform under a contact pressure while maintaining an electrical contactwith a substrate surface with reduced or minimal scratching of thesubstrate surface. In the embodiment shown in FIGS. 9A and 9B, thesubstrate surface may only contact the conductive elements 920 of thepolishing article 205. The conductive elements 920 are positioned so asto provide an uniform current density over the surface of the polishingarticle 205.

The conductive elements 920 are adhered to the conducting surface by anon-conductive, or dielectric, adhesive or binder. The non-conductiveadhesive may provide a dielectric coating to the conducting surface 940to provide an electrochemical barrier between the conducting surface 940and any surrounding electrolyte. The conducting surface 940 may be inthe form of a round polishing pad or a linear web or belt of polishingarticle 205. A series of perforations (not shown) may be disposed in theconducting surface 940 for provided flow of electrolyte therethrough.

While not shown, the conductive plate may be disposed on a support padof conventional polishing material for positioning and handling of thepolishing article 900 on a rotating or linear polishing platen.

FIG. 10A depicts a schematic perspective view of one embodiment of apolishing article 1000 comprised of conductive element 1004. Eachconductive element 1004 generally comprises a loop or ring 1006 having afirst end 1008 and a second end 1010 disposed in a depression 1012formed in the polishing surface 1024. Each conductive element 1004 maybe coupled to an adjoining conductive element to form a plurality ofloops 1006 extending above the polishing surface 1024.

In the embodiment depicted in FIG. 10A, each loop 1006 is fabricatedfrom a fiber coated by a conductive material and is coupled by a tiewire base 1014 adhered to the depression 1012. An example of the loop1006 is a nylon fiber coated with gold.

The contact height of the loop 1006 above the polishing surface may bebetween about 0.5 millimeter and about 2 millimeters and the diameter ofthe material comprising the loop may be between about 1 mil (thousandthsof an inch) and about 50 mils. The tie wire base 1014 may be aconductive material, such as titanium, copper, platinum, or platinumcoated copper. The tie wire base 1014 may also be coated by a layer ofconductive material, such as copper, that dissolves from the polishingpad article during polishing. The use of a layer of conductive materialon the tie wire base 1014 is believed to be a sacrificial layer thatdissolves in preference of the underlying loop 1006 material or tie wirebase 1014 material to extend the life of the conductive element 1004.The conductive elements 1004 may be orientated between 0 to 90 degreesrelative to a polishing surface 1024 and can be inclined in any polarorientation relative to a line normal to the polishing surface 1024. Theconductive elements 1004 are coupled to a power source by electricalconnectors 1030.

FIG. 10B depicts a schematic perspective view of another embodiment of apolishing article 1000 comprised of conductive element 1004. Theconductive element 1004 comprises a singular coil 1005 of a wirecomposed of a fiber coated with a conductive material as describedherein. The coil 1005 is coupled to a conductive member 1007 disposed ona base 1014. The coil 1005 may encircle the conductive member 1007,encircle the base 1014, or be adhered to the surface of the base 1014.The conductive bar may comprise a conductive material, such as gold, andgenerally comprises a conductive material that is chemically inert, suchas gold or platinum, with any electrolyte used in a polishing process.Alternatively, a layer 1009 of sacrificial material, such as copper, isdisposed on the base 1014. The layer 1009 of sacrificial material isgenerally a more chemically reactive material, such as copper, than theconductive member 1007 for preferential removal of the chemicallyreactive material compared to the material of the conductive member 1007and the coil 1005, during an electropolishing aspect, or anodicdissolution aspect, of the polishing process. The conductive member 1007may be coupled to a power source by electrical connectors 1030.

A biasing member may be disposed between the conductive elements and thebody to provide a bias that urges the conductive elements away from thebody and into contact with a substrate surface during polishing. Anexample of a biasing member 1018 is shown in FIG. 10B. However, theinvention contemplates that the conductive elements shown herein, forexample in FIGS. 8A-8D, 9A, 10A-10D, may use a biasing member. Thebiasing member may be a resilient material or device including acompression spring, a flat spring, a coil spring, a foamed polymer suchas foamed polyurethane (e.g., PORON® polymer), an elastomer, a bladderor other member or device capable of biasing the conductive element. Thebiasing member may also be a compliant or elastic material, such ascompliant foam or aired soft tube, capable of biasing the conductiveelement against and improve contact with the substrate surface beingpolished. The conductive elements biased may form a plane with thesurface of the polishing article or may extend above a plane of thesurface of the polishing article.

FIG. 10C shows a schematic perspective view of another embodiment of apolishing article 1000 having a plurality of conductive elements 1004,disposed in a radial pattern from the center of the substrate to theedge. The plurality of conductive elements may be displaced from eachother at intervals of 15°, 30°, 45°, 60°, and 90° degrees, or any othercombinations desired. The conductive elements 1004 are generally spacedto provide as uniform application of current or power for polishing ofthe substrate. The conductive elements may be further spaced so as tonot contact each other. Wedge portions 1004 of a dielectric polishingmaterial of the body 1026 may be configured to electrically isolate theconductive elements 1004. A spacer or recessed area 1060 is also formedin the polishing article to also isolate the conductive elements 1004from each other. The conductive elements 1004 may be in the form ofloops as shown in FIG. 10A or vertical extending fibers as shone in FIG.9B.

FIG. 10D depicts a schematic perspective view of an alternativeembodiment of the conductive element 1004 of FIG. 10A. The conductiveelement 1004 comprises a mesh or fabric of interwoven conductive fibers1006 as described herein having a first end 1008 and a second end 1010disposed in a depression 1012 formed in the polishing surface 1024 toform one continuous conductive surface for contact with the substrate.The mesh or fabric may be of one or more layers of interwoven fibers.The mesh or fabric comprising the conductive element 1004 is illustratedas a single layer in FIG. 10D. The conductive element 1004 may becoupled to a conductive base 1014 and may extend above the polishingsurface 1024 as shown in FIG. 10A. The conductive element 1004 may becoupled to a power source by electrical connectors 1030 connected to theconductive base 1014.

FIG. 10E shows a partial schematic perspective view of anotherembodiment of forming the conductive elements 1004 having loops 1006formed therein and securing the conductive elements to the body 1026 ofthe polishing article. Passages 1050 are formed in the body 1024 of thepolishing article intersecting grooves 1070 for the conductive elements1004. An insert 1055 is disposed in the passages 1050. The insert 1055comprises a conductive material, such as gold or the same material asthe conductive element 1006. Connectors 1030 may then be disposed in thepassages 1050 and contacted with the insert 1055. The connectors 1030are coupled to a power source. Ends 1075 of the conductive element 1004may be contacted with the insert 1055 for flow of power therethrough.The ends 1075 of the conductive element 1004 and the connectors 1030 arethen secured to the conductive insert 1055 by dielectric inserts 1060.The invention contemplated using the passages for every loop 1006 of theconductive element 1004, at intervals along the length of the conductiveelement 1004, or only at the extreme ends of the conductive element1004.

FIGS. 11A-C are a series of schematic side views illustrating theelastic ability of the loops or rings of conductive materials describedherein. A polishing article 1100 comprises a polishing surface 1110disposed on a sub-pad 1120 formed over a pad support 1130 with groovesor depressions 1140 therein. A conductive element 1142 comprising a loopor ring 1150 of a dielectric material coated by a conductive material isdisposed on a tie base 1155 in the depression 1170 and coupled with anelectrical contact 1145. A substrate 1160 is contacted with thepolishing article 1100 and moved in relative motion with the surface ofthe polishing article 1100. As the substrate contacts the conductiveelement 1142, the loop 1150 compresses into the depression 1140 whilemaintaining electrical contact with the substrate 1160 as shown in FIG.11B. When the substrate is moved a sufficient distance to no longercontact the conductive element 1142, the elastic loop 1150 returns tothe uncompressed shape for additional processing as shown in FIG. 11C.

Further examples of conductive polishing pads are described in U.S.Provisional Patent Application Ser. No. 10/033,732, filed Dec. 27, 2001,which is incorporated by reference in its entirety.

Power Application

Power may be coupled into the polishing articles 205 described above byusing a connector as described herein or a power transference device. Apower transference device is more fully detailed in U.S. ProvisionalPatent Application Ser. No. 10/033,732, filed Dec. 27, 2001, which isincorporated by reference in its entirety.

Referring back to FIGS. 11A-11C, power may be coupled to conductiveelements 1140 by the use of electrical contacts 1145 comprisingconductive plates or mounts disposed in the grooves or depressions 1170formed in the polishing pad. In the embodiment shown in FIG. 11A, theconductive elements 1140 are mounted on plates of a metal, such as gold,which are mounted on a support, such as disc 206, with the polishingarticle 1100 as shown in FIG. 2. Alternatively, the electrical contactsmay be disposed on a polishing pad material between a conductiveelements and a polishing pad material, for example, between theconductive element 840 and the body 810 as shown in FIGS. 8A and 8B. theelectrical contacts are then coupled to a power source by leads (notshown) as described above in FIGS. 8A-8D.

FIGS. 12A-12D are top and side schematic view of embodiments of apolishing article having extensions connected to a power source (notshown). The power source provides the current carrying capability, i.e.,the anodic bias to a substrate surface for anodic dissolution in an ECMPprocess. The power source may be connected to the polishing article byone or more conductive contacts disposed around the conductive polishingportion and/or the article support portion of the polishing article. Oneor more power sources may be connected to the polishing article by theone or more contacts to allow for generating variable bias or currentacross a portion of the substrate surface. Alternatively, one or moreleads may be formed in the conductive polishing portion and/or thearticle support portion, which are coupled to a power source.

FIG. 12A is a top plan view of one embodiment of a conductive polishingpad coupled to a power source by a conductive connector. The conductivepolishing portion may have extensions, for example, a shoulder orindividual plugs, formed in the conductive polishing portion 1210 with agreater width or diameter than the article support portion 1220. Theextensions are coupled to a power source by a connector 1225 to provideelectrical current to the polishing article 205. In FIG. 12B, extensions1215 may be formed to extend parallel or laterally from the plane of theconductive polishing portion 1210 and extending beyond the diameter ofthe polishing support portion 1220. The pattern of the perforation andgrooving are as shown in FIG. 6.

FIG. 12B is a cross-section schematic view of one embodiment of aconnector 1225 coupled to a power source (not shown) via a conductivepathway 1232, such as a wire. The connector comprises an electricalcoupling 1234 connected to the conductive pathway 1232 and electricallycoupled to the conductive polishing portion 1210 of the extension 1215by a conductive fastener 1230, such as a screw. A bolt 1238 may becoupled to the conductive fastener 1230 securing the conductivepolishing portion 1210 therebetween. Spacers 1236, such as washer, maybe disposed between the conductive polishing portion 1210 and thefastener 1230 and bolt 1238. The spacers 1236 may comprise a conductivematerial. The fastener 1230, the electrical coupling 1234, the spacers1236, and the bolt 1238 may be made of a conductive material, forexample, gold, platinum, titanium, aluminum, or copper. If a materialthat may react with the electrolyte is used, such as copper, thematerial may be covered in a material that is inert to reactions withthe electrolyte, such as platinum. While not shown, alternativeembodiments of the conductive fastener may include a conductive clamp,conductive adhesive tape, or a conductive adhesive.

FIG. 12C is a cross-section schematic view of one embodiment of aconnector 1225 coupled to a power source (not shown) via a support 1260,such as the upper surface of a platen or disc 206 as shown in FIG. 2.The connector 1225 comprises a fastener 1240, such as a screw or bolthaving sufficient length to penetrate through the conductive polishingportion 1210 of the extension 1215 to couple with the support 1260. Aspacer 1242 may be disposed between the conductive polishing portion1210 and the fastener 1240.

The support is generally adapted to receive the fastener 1240. Anaperture 1246 may be formed in the surface of the support 1260 toreceive the fastener as shown in FIG. 12C. Alternatively, an electricalcoupling may be disposed between the fastener 1240 and the conductivepolishing portion 1210 with the fastener coupled with a support 1260.The support 1260 may be connected to a power source by a conductivepathway 1232, such as a wire, to a power source external to a polishingplaten or chamber or a power source integrated into a polishing platenor chamber to provide electrical connection with the conductivepolishing portion 1210. The conductive path 1232 may be integral withthe support 1260 or extend from the support 1260 as shown in FIG. 12B

In a further embodiment, the fastener 1240 may be an integratedextension of the support 1260 extending through the conductive polishingportion 1215 and secured by a bolt 1248 as shown in FIG. 12D.

FIGS. 12E and 12F show side schematic and exploded perspective views ofanother embodiment of providing power to a polishing article 1270 havinga power coupling 1285 disposed between a polishing portion 1280 and aarticle support portion 1290. The polishing portion 1280 may be made ofa conductive polishing material as described herein or include aplurality of conductive elements 1275 as described herein. Theconductive elements 1275 may be physically isolated from one another asshown in FIG. 12F. The conductive elements 1275 formed in the polishingsurface are adapted to electrically contact the power coupling 1285,such as by a conductive base of the element.

The power coupling 1285 may comprise a wire interconnecting elements1275, multiple parallel wires interconnecting elements 1275, multiplewires independently connecting elements 1275, or a wire meshinterconnecting elements connecting elements 1275 to one or more powersources. Independent power sources coupled to independent wires andelements may have varied power applied while interconnected wires andelements may provide uniform power to the elements. The power couplingmay cover a portion or all of the diameter or width of the polishingarticle. The power coupling 1285 in FIG. 12F is an example of a wiremesh interconnecting elements connecting elements 1275. The powercoupling 1285 may be connected to a power source by a conductive pathway1287, such as a wire, to a power source external to a polishing platenor chamber or a power source integrated into a polishing platen orchamber.

Abrasive Elements in Polishing Surfaces

FIGS. 13A-B are top and sectional views of another embodiment of aconductive article 1400. The conductive article 1400 includes abrasivefeatures extending from a polishing surface 1402 of a conductive portion1404 of the conductive article 1400. The abrasive features may beabrasive particles as described with reference to FIG. 3 above, or maybe discreet abrasive elements 1406 as shown in FIGS. 13A-B.

In one embodiment, the abrasive elements 1406 are bars received inrespective slots 1408 formed in the polishing surface 1402 of theconductive article 1400. The abrasive elements 1406 generally extendfrom the polishing surface 1402 and are configured to remove thepassivation layer of the metal surface of the substrate being polished,thereby exposing the underlying metal to the electrolyte andelectrochemical activity, thereby enhancing the rate of polishing duringprocessing. The abrasive elements 1406 may be formed from ceramic,inorganic, organic, or polymer material strong enough to break thepassivation layer formed at the metal surface. An example is a bar orstrip made from conventional polishing pad such as polyurethane paddisposed in the conductive article 1400. In the embodiment depicted inFIGS. 13A-B, the abrasive elements 1406 may have hardness of at leastabout 30 Shore D, or hard enough to abrade the passivation layer of thematerial being polished. In one embodiment, the abrasive elements 1406are harder than copper. Polymer particles may be solid or spongy totailor the wear rate of the abrasive elements 1406 relative to thesurrounding conductive portion 1404.

The abrasive elements 1406 may be configured in various geometric orrandom configurations on the polishing surface 1402. In one embodiment,the abrasive elements 1406 are radially oriented on the polishingsurface 1402, however, other orientations such as spiral, grid, paralleland concentric orientations of the abrasive elements 1406 arecontemplated among other orientations.

In one embodiment, a resilient member 1410 may be disposed in therespective slots 1408 between the abrasive elements 1406 and theconductive portion 1404. The resilient member 1410 allows the abrasiveelements 1406 to move relative to the conductive portion 1404, therebyproviding enhanced compliance to the substrate for more uniform removalof the passivation layer during polishing. Moreover, the compliance ofthe resilient member 1410 may be selected to tailored the relativepressure applied to the substrate by the abrasive elements 1406 and thepolishing surface 1402 of the conductive portion 1404, thereby balancingremoval rate of the passivation layer against the rate of passivationlayer formation so that the metal layer being polished is minimallyexposed to the abrasive elements 1406 to minimize potential scratchgeneration.

Conductive Balls Extending from Polishing Surfaces

FIGS. 14A-D are top and sectional views of alternative embodiments of aconductive article 1500. The conductive article 1500 includes conductiverollers 1506 extending from a polishing surface 1502 of an upper portion1504 of the conductive article 1500. The rollers 1506 can be urged downto the same plane of the polishing surface 1502 by substrate duringpolishing. The conductive rollers embedded in the conductive article1500 are coupled to an external power source 1536 at high voltage forhigh removal rate of bulk polishing substrate during processing.

The conductive rollers 1506 may be fixed relative to the upper portion1504, or may be free to roll. The conductive rollers 1506 may balls,cylinders, pins, ellipsoidal or other shapes configured not to scratchthe substrate during processing.

In the embodiment depicted in FIG. 14B, the conductive rollers 1506 areplurality of balls disposed in one or more conductive carriers 1520.Each conductive carrier 1520 is disposed in a slot 1508 formed in thepolishing surface 1502 of the conductive article 1500. The conductiverollers 1506 generally extend from the polishing surface 1502 and areconfigured to provide electrical contact with the metal surface of thesubstrate being polished. The conductive rollers 1506 may be formed fromany conductive material, or formed from a core 1522 at least partiallycoated with a conductive covering 1524. In the embodiment depicted inFIG. 14B, the conductive rollers 1506 have a polymer core 1522 at leastpartially covered by a soft conductive material 1524. An example is aTORLON™ polymer core coated with conductive gold layer using copper asseeding layer between TORLON™ and gold layer. Another example is TORLON™or other polymer core coated with a layer of copper or other conductivematerial. Other soft conductive materials 1524 include, but are notlimited to, silver, copper, tin and the like.

In one embodiment, the polymer core 1522 may be selected from an elasticor a resilient material such as polyurethane that deformed when theroller 1506 is in contact with a substrate during polishing. Someexamples of materials that may be utilized for the core 1522 includeelastic organic polymers, ethylene-propylene-diene (EDPM), poly-alkenes,polyalkynes, polyesters, poly-aromatic alkenes/alkynes, polyimide,polycarbonate, polyurethane, and there combinations. Other examples ofcore materials include inorganic polymers, such as siloxane, or organicand inorganic combined materials, such as polysilicon and polysilane. Asthe roller 1506 deforms, the contact area between the roller 1506 andsubstrate increases, thus improving the current flow between the roller1506 and conductive layer disposed on the substrate and therebyimproving polishing results.

Alternatively, the polymer core 1522 may be made conductive as to makethe covering of the core 1522 with soft conductive material 1524optional. For example, the polymer core 1522 may be doped by otherconductive elements, such as metals, conductive carbon or graphite,among other conductive materials.

The conductive rollers 1506 may be arranged in various geometric orrandom configurations on the polishing surface 1502. In one embodiment,the conductive rollers 1506 are radially oriented on the polishingsurface 1502, however, other orientations such as spiral, grid, paralleland concentric orientations of the conductive rollers 1506 arecontemplated among other orientations.

In the embodiment depicted in FIG. 14B, a resilient member 1510 may bedisposed in the respective slots 1508 between the conductive carriers1520 and the conductive portion 1504. The resilient member 1510 allowsthe conductive rollers 1506 (and carrier 1520) to move relative to theconductive portion 1504, thereby providing enhanced compliance to thesubstrate for more uniform electrical contact during polishing.

In the embodiment depicted in FIG. 14C, the conductive rollers 1506 arerespectively disposed in a plurality of electrically insulative housings1530 that are coupled to the disc 206. Each housing 1530 may be coupledto the disc 206 by welding, adhesives, staking or other methods. In theembodiment depicted in FIG. 14C, the housings 1530 are threaded into thedisc 206.

The housing 1530 is generally a hollow cylinder that allows the roller1506 to move vertically, perpendicular to the plane of the disc 206 andpolishing surface 1502. An upper end of the housing 1530 includes atapered seat 1532 that prevents the roller 1506 from exiting through theupper end of the housing 1530. The seat 1532 is configured to allow atleast a portion of the perimeter of the roller 1506 to extend out of thehousing 1530 and contact the substrate 114 during processing.

A contact means 1534 is configured to maintain electrical contactbetween the roller 1506 and the power source 1536. The contact means1534 may be any type of conductive resilient member such as a springform, compression spring, conductive bearing and the like, or otherdevice that allows electrical connection to be maintains betweendifferent positions of the roller 1506 within the housing 1530. Thecontact means 1534 is disposed in the lower end of each of the housings1530. In one embodiment, the contact means 1534 is a flat spring. Thecontact means 1534 may be utilized to bias the roller 1506 away from thedisc 206 and against the seat 1532.

Alternatively, electrolyte provided from an electrolyte source 1544flowing through the housing 1530 and exiting the housing 1530 betweenthe seat 1532 and roller 1506. The flow of electrolyte exiting thehousing 1530 biases the roller 1506 away from the disc 206.

In yet another embodiment, the roller 1506 may be configured with aspecific gravity less than the electrolyte so that the buoyancy of theroller 1506 when the housing 1530 is at least partially filled withelectrolyte biases the roller 1506 away from the disc 206. The roller1506 may be optionally hollow to increase the buoyancy and decrease theinertia of the roller 1506. One housing having a roller coupled to apower source through a contact member that may be adapted to benefitfrom the invention is described in previously incorporated U.S. patentapplication Ser. No. 10/211,626.

A pad assembly 1540 is disposed on the disc 206. The pad assembly 1540includes a plurality of first apertures 1542 that are configured toallow the housings 1530 to extend at least partially therethrough.Generally, the housing 1530 has a height configured to allow a portionof the perimeter of the roller 1506 to extend above the pad assembly1540 so that the roller 1506 may be displaced to a positionsubstantially flush with the polishing surface 1502 of the pad assembly1540 by the substrate 114 during processing.

In the embodiment depicted in FIG. 14C, the pad assembly 1540 includes adielectric layer 1550, a subpad 1552 and an electrode 1554. Thedielectric layer 1550, the subpad 1552 and the electrode 1554 may becoupled together as a replaceable unit, for example by compressionmolding, staking, fastening, adhering, bonding or by other couplingmethods.

The dielectric layer 1550 may be similar to the conductive portion 310described above. The subpad 1552 may be similar to the article supportportion 320 described above. The electrode 1554 may be similar to theelectrode 204 described above.

A second set of apertures 1545 (one of which is shown in FIG. 14C) maybe formed at least through the dielectric layer 1550 through at leastthe dielectric layer 1550 and the subpad 1552 to allow electrolytedisposed on the pad assembly 1540 to provide a current path between theelectrode 1554 and the substrate 114. Optionally, the apertures 1545 mayextend into or through the electrode 1554. The apertures 1545 maypermeable and/or porous portion of the dielectric layer 1550 and thesubpad 1552. A window (not shown) may also be formed in the pad assembly1540 as described above with reference to FIG. 7F to facilitate processcontrol.

In the embodiment depicted in FIG. 14D, a pad assembly 1560 includes atleast a conductive layer 1562, a subpad 1564 and an electrode 1554. Theconductive layer 1562, the subpad 1564 and the electrode 1554 may becoupled together as a replaceable unit. The pad assembly 1560 mayinclude first apertures 1570 configured to accept the housing 1530 andsecond apertures 1572 to allow electrolyte disposed on the pad assembly1560 to establish a current path between the substrate 114 and theelectrode 1554. The second apertures 1572 may alternatively be a porousand/or permeable portion of the pad assembly 1560. A window (not shown)may also be formed in the pad assembly 1560 as described above

In one embodiment, the conductive layer 1562 and subpad 1564 may beconfigured similar to the conductive layer 310 and article supportportion 320 of the polishing article 205 described above. Alternatively,the pad assembly 1560 may include a conductive backing 1566 and aninterposed pad 1568 disposed between the conductive layer 1562 andsubpad 1564. The conductive backing 1566 and the interposed pad 1568 maybe similarly configured to the conductive backing and the interposed paddescribed under the heading “CONDUCTIVE ARTICLE WITH INTERPOSED PAD”that follows below.

The conductive backing 1566 is generally coupled to the power source1536 through a switch 1574. The conductive backing 1566 distributes thepotential uniformly across the backside of the conductive layer 1562 sothat uniform current is delivered across the diameter of the substrate114 between the conductive layer 1562 and substrate 114 duringprocessing.

During processing, the switch 1574 is disposed in a first state thatelectrically couples the roller 1506 to the power source 1536 whileopening the circuit between the conductive backing 1566 and the powersource 1536. The rollers 1506 allow relatively high current flow betweenthe substrate 114 and electrode 1554 thereby facilitating bulk removalof a conductive layer from the substrate. Once the conductive layer issubstantially removed, the switch 1574 is disposed in a second statethat electrically couples conductive backing 1566 the to the powersource 1536 while opening the circuit between the roller 1506 and thepower source 1536. The conductive backing 1566 provides substantiallyuniform voltage potential across the width of the conductive layer 1562to facilitate removal of residual conductive material from thesubstrate. Thus, both bulk and residual conductive material removal fora substrate may be performed on a single platen without lifting thesubstrate from the pad assembly 1540. Examples of other pad assemblythat may be adapted to benefit from the invention is described belowwith reference to FIGS. 15-17. It is also contemplated that other padassemblies may be utilized, including those described above and thoseincorporating windows that facilitate sensing polishing performance.

Conductive Article with Interposed Pad

FIG. 15 is a sectional view of another embodiment of a conductivearticle 1600. The conductive article 1600 generally includes aconductive portion 1602 adapted to contact a substrate during polishing,an article support portion 1604 and an interposed pad 1606 sandwichedbetween the conductive portion 1602 and the article support portion1604. The conductive portion 1602 and article support portion 1604 maybe configured similar to any of the embodiments described herein ortheir equivalent. A layer of adhesive 1608 may be provided on each sideof the interposed pad 1606 to couple the interposed pad 1606 to thearticle support portion 1604 and the conductive portion 1602. Theconductive portion 1602, the article support portion 1604 and theinterposed pad 1606 may be coupled by alternative methods therebyallowing the components of the conductive article 1600 to be easilyreplaced as a single unit after its service life, simplifyingreplacement, inventory and order management of the conductive article1600.

Optionally, the support portion 1604 may be coupled to an electrode 204and replaceable with the conductive article 1600 as a single unit. Theconductive article 1600, optionally including the electrode 204, mayalso include a window formed therethrough as depicted and described withreference to FIG. 7F.

The interposed pad 1606 is generally harder than the article supportportion 1604 and is a hard or harder than the conductive portion 1602.The invention contemplates the interposed pad 1606 may alternatively besofter than the conductive portion 1602. The hardness of the interposedpad 1606 is selected to provide stiffness to the conductive article1600, which extends the mechanical life of both the conductive portion1602 and the article support portion 1604 while improving dampeningcharacteristics of the conductive article 1600 resulting in greaterglobal flatness of the polished substrate. In one embodiment, theinterposed pad 1606 has a hardness of less than or equal to about 80Shore D, the article support portion 1604 has a hardness of less than orequal to about 80 Shore A, while the conductive portion 1602 has ahardness of less than or to about 100 Shore D. In another embodiment,the interposed pad 1606 has a thickness of less than or equal to about35 mils, while the article support portion 1604 has a thickness of lessthan or equal to about 100 mils.

The interposed pad 1606 may be fabricated from a dielectric materialthat permits electrical pathways to be established through the laminatecomprising the conductive article 1600 (i.e., the stack of theconductive portion 1602, the interposed pad 1606 and the article supportportion 1604). The electrical pathways may be established as theconductive article 1600 is immersed or covered with a conductive fluid,such as an electrolyte. To facilitate the establishment of electricalpathways through the conductive article 1600, the interposed pad 1606may be at least one of permeable or perforated to allow electrolyte toflow therethrough.

In one embodiment, the interposed pad 1606 is fabricated from adielectric material compatible with the electrolyte and theelectrochemical process. Suitable materials include polymers, such aspolyurethane, polyester, mylar sheet, epoxy and polycarbonate, amongothers.

Optionally, a conductive backing 1610 may be disposed between theinterposed pad 1606 and the conductive portion 1602. The conductivebacking 1610 generally equalizes the potential across the conductiveportion 1602, thereby enhancing polishing uniformity. Having equalpotential across the polishing surface of the conductive portion 1602ensures good electrical contact between the conductive portion 1602 andconductive material being polished, particularly if the conductivematerial is residual material that is not longer a continuous film(i.e., discrete islands of film residue). Moreover, the conductivebacking 1610 provides mechanical strength to the conductive portion1602, thereby increasing the service life of the conductive article1600. Utilization of the conductive backing 1610 is beneficial inembodiments where the resistance through the conductive portion isgreater than about 500 m-ohms and enhances the mechanical integrity ofconductive portion 1602. The conductive backing 1610 may also beutilized to enhance the conductive uniformity and lower the electricalresistance of the conductive portion 1602. The conductive backing 1610may be fabricated from metal foils, metal screens, metal coated woven ornon-woven fabrics among other suitable conductive materials compatiblewith the polishing process. In one embodiment, the conductive backing1610 is compression molded to the conductive portion 1602. The backing1610 is configured not to prevent the flow of electrolyte between theconductive portions 1604 and the interposed pad 1606. The conductiveportion 1602 may be mounted onto the conductive backing 1610 throughcompression molding, lamination, injection molding and other suitablemethods.

FIG. 16 is sectional view of another embodiment of a conductive article1700. The conductive article 1700 generally includes a conductiveportion 1602 adapted to contact a substrate during polishing, aconductive backing 1610, an article support portion 1604 and aninterposed pad 1706 sandwiched between the conductive portion 1602 andthe article support portion 1604, having similar construction to theconductive article 1600 described above.

In the embodiment depicted in FIG. 16, the interposed pad 1706 isfabricated from a material having a plurality of cells 1708. The cells1708 are generally filled with air or other fluid, and provide aresiliency and compliance that enhances processing. The cells may beopen or closed with a size ranging from 0.1 micron meter to severalmillimeters such as between 1 micron meter to 1 millimeter. Theinvention contemplates other sizes applicable for interposed pad 1706.The interposed pad 1706 may be at least one of permeable or perforatedto allow electrolyte to flow therethrough.

The interposed pad 1706 may be fabricated from a dielectric materialcompatible with the electrolyte and the electrochemical process.Suitable materials include, but are not limited to, foamed polymers suchas foamed polyurethane and mylar sheet. The interposed pad 1706generally has a less compressibility than article support portion orsub-pad 1604 and more local deformation independence when subjected topressure.

FIG. 17 is sectional view of another embodiment of a conductive article1800. The conductive article 1800 includes a conductive portion 1802coupled to an article support portion 1804. Optionally, the conductivearticle 1800 may include an interposed pad and conductive backing (bothnot shown) disposed between the conductive portion 1802 and the articlesupport portion 1804.

The conductive article 1800 generally includes a plurality of apertures1806 formed therethrough to allow electrolyte or other processing fluidsto pass between an upper polishing surface 1808 of the conductiveportion 1802 and a lower mounting surface 1810 of the article supportportion 1804. The edge 1812 defined where each of the apertures 1806intersects the upper polishing surface 1808 is contoured to eliminateany sharp corner, burrs or surface irregularities that may scratch thesubstrate during processing. The contour of the edge 1812 may include aradius, chamfer, taper or other configuration that smoothes the edge1812 and promotes scratch minimization.

In embodiments where the conductive portion 1802 is at least partiallyfabricated from a polymer, the smoothing of the edge 1812 may berealized by forming the aperture 1806 before the polymer has completelycured. Thus, the edges 1812 will become rounded as the conductiveportion 1802 shrinks during the remainder of polymer curing cycle.

Additionally, or in the alternative, the edges 1812 may be rounded byapplying at least one of heat or pressure during or after curing. In oneexample, the edges 1812 may be burnished, heat or flame treated to roundthe transition between the polishing surface 1808 and the aperture 1806at the edge 1812.

In another example, a polymer conductive portion 1802 may be comprisesof a moldable material that is repulsive to the mold or die. Therepulsive nature of polymer conductive portion 1802 causes a surfacetension that causes stresses to be molded into the polymer conductiveportion 1802 that pull the material away from the mold, therebyresulting in the rounding of the edges 1812 of the apertures 1806 uponcuring.

The apertures 1806 may be formed through the conductive article 1800before or after assembly. In one embodiment, the aperture 1806 includesa first hole 1814 formed in the conductive portion 1802 and a secondhole 1816 formed in the article support portion 1804. In embodimentscomprising an interposed pad, the second hole 1816 is formed therein.Alternatively, the first hole 1814 and at least a portion of the secondhole 1816 may be formed in the conductive portion 1802. The first hole1814 has a diameter greater than a diameter of the second hole 1816. Thesmaller diameter of the second hole 1816 underlying the first hole 1814provides lateral support to the conductive portion 1802 surrounding thefirst hole 1814, thereby improving resistance to pad shear and torqueduring polishing. Thus, the aperture 1806 comprising a larger hole atthe surface 1808 disposed concentric to an underlying smaller holeresults in less deformation of the conductive portion 1802 whileminimizing particle generation, thus minimizing substrate defectsincurred by pad damages.

The apertures in conductive article may be punched through mechanicalmethods such as male/female punching before or after all layers are puttogether. In one embodiment the conductive portion 1802 compressionmolded onto conductive backing is first mounted onto interposed layer,conductive portion 1802 with conductive backing and interposed layer aremechanically perforated together, the article support portion or sub-padis mechanically perforated separately, after perforation they arealigned together. In another embodiment all layers are put together,then perforated. The invention contemplates any perforation techniquesand sequence.

FIG. 18 is a partial sectional view of another embodiment of an ECMPstation 1990 and FIGS. 19A-B are side and exploded views of a ballassembly 1900 of the ECMP station 1990 of FIG. 19. The ECMP station 1990includes a platen 1950 that supports a polishing pad assembly 1960 onwhich a substrate 114 retained in a polishing head 130 is processed. Theplaten 1950 includes at least one ball assembly 1900 projectingtherefrom and coupled to a power source 1972 that are adapted to bias asurface of the substrate 114 during processing. Although two ballassemblies 1900 are shown in FIG. 18, any number of ball assemblies maybe utilized and may be distributed in any number of configurationsrelative to the centerline of the platen 1950.

The polishing pad assembly 1960 may be any pad assembly suitable forprocessing the substrate, including any of the embodiments describedabove. The polishing pad assembly 1960 may include an electrode 1962 anda polishing layer 1966. In one embodiment, the polishing layer 1966 ofthe polishing pad assembly 1960 may include a polishing surface 1964that is dielectric, such as a polyurethane pad. In another embodiment,the polishing layer 1966 of the polishing pad assembly 1960 may includea polishing surface 1964 that is conductive, such as a polymer matrixhaving conductive particles dispersed therein or a conductive coatedfabric, among others. In the embodiment wherein the polishing surface1964 is conductive, the polishing surface 1964 and electrode 1962 may becoupled to the power source 1972 (shown by the dashed lines) via aswitch 1974 that allows power to be selectively switch between the ballassemblies 1900 and the conductive polishing surface 1964 torespectively facilitate bulk metal removal and residual metal removalfrom the substrate 114 without lifting the substrate 114 from thepolishing pad assembly 1960.

In one embodiment, a passage 1955 permeable to electrolyte is disposedor formed at least through the polishing layer 1966. The passage 1955allows electrolyte to establish a conductive path between the substratepositioned on the polishing layer 1966 and the electrode 1962. In theembodiment depicted in FIG. 18, the passage 1955 is formed through thepolishing layer 1966. Alternatively, the passage 1955 may extendcompletely through the polishing layer 1666 and the electrode 1962 (asshown in phantom). In another embodiment, the passage 1955 may be apermeable portion of the polishing layer 1966.

The ball assemblies 1900 are generally coupled to the platen 1950 andextend at least partially through respective apertures 1968 formed inthe polishing pad assembly 1960. Each of the ball assemblies 1900include a hollow housing 1902, an adapter 1904, a ball 1906, a contactelement 1914 and a clamp bushing 1916. The ball 1906 is movably disposedin the housing 1902, and may be disposed in a first position having atleast a portion of the ball 1906 extending above the polishing surface1964 and at least a second position where the ball 1906 is flush withthe polishing surface 1964. The ball 1906 is generally suitable forelectrically biasing the substrate 114 and may be configured asdescribed above.

The housing 1902 is fabricated from a dielectric material compatiblewith process chemistries. In one embodiment, the housing 1902 is made ofPEEK. The housing 1902 has a first end 1908 and a second end 1910. Adrive feature 1912 is formed in and/or on the first end 1908 tofacilitate installation of the ball assembly 1900 to the platen 1950.The drive feature 1912 may be holes for a spanner wrench, a slot orslots, a recessed drive feature (such as for a TORX® or hex drive, andthe like) or a projecting drive feature (such as wrench flats or a hexhead, and the like), among others. The first end 1908 additionallyincludes a seat 1926 that prevents the ball 1906 from passing out of thefirst end 1908 of the housing 1902.

The contact element 1914 is coupled between the clamp bushing 1916 andadapter 1904. The contact element 1914 is generally configured toelectrically connect the adapter 1904 and ball 1906 substantially orcompletely through the range of ball positions within the housing 1902.The contact element 1914 may be configured as described above.

In the embodiment depicted in FIGS. 18-19A-B and detailed in FIG. 20,the contact element 1914 includes an annular base 1942 having aplurality of flexures 1944 extending therefrom in a polar array. Theflexure 1944 includes two support elements 2102 extending from the base1942 to a distal end 2108. The support elements 2102 are coupled by aplurality of rungs 2104 to define apertures 2110 that facilitate flowpast the contact element 1916 with little pressure drop as discussedfurther below. A contact pad 2106 adapted to contact the ball 1906couples the support elements 2102 at the distal end 2108 of each flexure1944. The flexure 1944 is generally fabricated from a resilient andconductive material suitable for use with process chemistries. In oneembodiment, the flexure 1944 is fabricated from gold plated berylliumcopper.

Returning to FIGS. 17 and 18A-B, the clamp bushing 1916 includes aflared head 1924 having a threaded post 1922 extending therefrom. Theclamp busing may be fabricated from either a dielectric or conductivematerial, and in one embodiment, is fabricated from the same material asthe housing 1902. The flared head 1924 maintains the flexures 1944 at anacute angle relative to the centerline of the ball assembly 1900 so thatthe contact pads 2106 of the contact elements 1914 are positioned tospread around the surface of the ball 1906 to prevent bending, bindingand/or damage to the flexures 1944 during assembly of the ball assembly1900 and through the range of motion of the ball 1906.

The post 1922 of the clamp bushing 1916 is disposed through a hole 1946in the base 1942 and threads into a threaded portion 1940 of a passage1936 formed through the adapter 1904. A passage 1918 formed through theclamp bushing 1916 includes a drive feature 1920 at an end disposed inthe flared head 1924. Similarly, the passage 1936 includes a drivefeature 1938 in an end opposite the threaded portion 1940. The drivefeatures 1920, 1930 may be similar to those described above, and in oneembodiment, are hexagonal holes suitable for use with a hex driver. Theclamp bushing 1924 is tightened to a level that ensures good electricalcontact between the contact element 1914 and the adapter 1904 withoutdamaging the contact element 1914 or other component.

The adapter 1904 is generally fabricated from an electrically conductivematerial compatible with process chemistries, and in one embodiment, isfabricated from stainless steel. The adapter 1904 includes an annularflange 1932 having a threaded post 1930 extending from one side and aboss 1934 extending from the opposite side. The threaded post 1930 isadapted to mate with a contact plate 1980 disposed in the platen 1950which couples the respective balls 1906 in the ball assemblies 1900 tothe power source 1972.

The boss 1934 is received in the second end 1910 of the housing 1902 andprovides a surface for clamping the contact element 1914 thereto. Theboss 1934 additionally includes at least one threaded hole 2006 disposedon the side of the boss 1934 that engages a fastener 2002 disposedthrough a hole 2004 formed in the housing 1902, thereby securing thehousing 1902 to the adapter 1904 and capturing the ball 1906 therein. Inthe embodiment depicted in FIG. 19A, three fasteners are shown forcoupling the housing 1902 to the adapter 1904 through counter-sunk holes2004. It is contemplated that the housing 1902 and adapter 1904 may befastened by alternative methods or devices, such as staking, adhering,bonding, press fit, dowel pins, spring pins, rivets and retaining rings,among others.

The ball 1904 is generally actuated towards the polishing surface 1906by at least one of spring, buoyant or flow forces. In the embodimentdepicted in FIG. 18, the passages 1936, 1918 formed through the adapter1904 and clamp busing 1916 are coupled through the platen 1950 to anelectrolyte source 1970. The electrolyte source 1970 provideselectrolyte through the passages 1936 and 1918 into the interior of thehollow housing 1902. The electrolyte exits the housing 1902 between theseat 1926 and ball 1906, thus causing the ball 1906 to be biased towardthe polishing surface 1964 and into contact with the substrate 114during processing.

So that the force upon the ball 1906 is consistent across the differentelevations of the ball 1906 within the housing 1906, a relief or groove1928 is formed in the interior wall of the housing 1906 to accept thedistal ends (2108 in FIG. 20) of the flexures 1944 to preventrestricting the flow of electrolyte passing the ball 1908. An end of thegroove 1928 disposed away from the seat 1926 is generally configured tobeing at or below the diameter of the ball 1906 when the ball 1906 is inthe lowered position.

FIGS. 21-23 are perspective and sectional views of another embodiment ofa conductive article having another embodiment of a ball assembly.

FIG. 21 is a perspective view of another embodiment of an ECMP station2290 and FIGS. 22-23 are perspective and partial sectional views of aball assembly 2200 of the ECMP station 2290 of FIG. 21. The ECMP station2290 includes a platen 2250 that supports a polishing pad assembly 2260(partially shown in FIG. 22). The platen 2250 includes at least one ballassembly 2200 projecting therefrom and coupled to a power source 1972.The ball assembly 2200 is adapted to electrically bias a surface of thesubstrate 114 (shown in FIG. 23) during processing. Although one ballassembly 2200 is shown coupled to the center of the platen 2250 in FIG.21, any number of ball assemblies may be utilized and may be distributedin any number of configurations relative to the centerline of the platen2250.

The polishing pad assembly 2260 may be any pad assembly suitable forprocessing the substrate, including any of the embodiments describedabove. The polishing pad assembly 2260 may include an electrode 2462 anda polishing layer 2466. In one embodiment, the polishing layer 2466 ofthe polishing pad assembly 2260 may include a polishing surface 2464that is dielectric, such as a polyurethane pad. In another embodiment,the polishing layer 2466 of the polishing pad assembly 2260 may includea polishing surface 2464 that is conductive, such as a polymer matrixhaving conductive particles dispersed therein or a conductive coatedfabric, among others. In the embodiment wherein the polishing surface2464 is conductive, the polishing surface 2464 and electrode 2462 may becoupled to the power source 1972 (shown by the dashed lines) via aswitch 1974 that allows power to be selectively switch between the ballassembly 2200 and the conductive polishing surface 2464 to respectivelyfacilitate bulk metal removal and residual metal removal from thesubstrate 114 without lifting the substrate 114 from the polishing padassembly 2260.

In one embodiment, a permeable passage 2455 is disposed at least throughthe polishing layer 2466 and extends at least up to the electrode 2462.Alternatively, the passage 2455 may extend completely through thepolishing layer 2466 and the electrode 2462 (as shown in phantom). Thepassage 2455 allows an electrolyte to establish a conductive pathbetween the substrate and the electrode 2462. In one embodiment, thepassage 2455 comprises a permeable portion of the polishing layer 2466.In another embodiment, the passage 2455 is a hole formed in thepolishing layer 2466.

The ball assembly 2200 is generally coupled to the platen 2250 andextends at least partially through an aperture 2468 formed in thepolishing pad assembly 2260. The ball assembly 2200 include a housing2302 that retains a plurality of balls 1906. The balls 1906 are movablydisposed in the housing 2302, and may be disposed in a first positionhaving at least a portion of the balls 1906 extending above thepolishing surface 2464 and at least a second position where the balls1906 are flush with the polishing surface 2464. The balls 1906 aregenerally suitable for electrically biasing the substrate 114 and may beconfigured as described above.

The housing 2302 is removably coupled to the platen 2250 to facilitatereplacement of the ball assembly 2200 after a number of polishingcycles. In one embodiment, the housing 2302 is coupled to the platen2250 by a plurality of screws 2308. The housing 2302 includes an upperhousing 2304 coupled to a lower housing 2306 that retain the balls 1906therebtween. The upper housing 2304 is fabricated from a dielectricmaterial compatible with process chemistries. In one embodiment, theupper housing 2304 is made of PEEK. The lower housing 2306 is fabricatedfrom a conductive material compatible with process chemistries. In oneembodiment, the lower housing 2306 is made of stainless steel. The lowerhousing 2306 is coupled to the power source 1972. The housings 2304,2306 may be coupled in any number of methods, including but not limitedto, screwing, bolting, riveting, bonding, staking and clamping, amongothers. In the embodiment depicted in FIGS. 21-23, the housings 2304,2306 are coupled by a plurality of screws 2408.

The balls 1906 are disposed in a plurality of apertures 2402 formedthrough the housings 2304, 2306. An upper portion of each of theapertures 2402 includes a seat 2404 that extends into the aperture 2402from the upper housing 2304. The seat 2404 is configured to prevent theball 1906 from exiting the top end of the aperture 2402.

A contact element 1914 is disposed in each aperture 2402 to electricallycouple the ball 1906 to the lower plate 2306. Each of the contactelement 1914 is coupled to the lower plate 2306 by a respective clampbushing 1916. In one embodiment, a post 1922 of the clamp bushing 1916is threaded into a threaded portion 2410 of the aperture 2402 formedthrough the housing 2302.

The upper portion of each of the apertures 2402 includes a relief orgroove 2406 formed in the upper housing 2304. The groove 2406 isconfigured receive the distal portions of the contact element 1914,thereby preventing restriction of electrolyte flowing between the ball1906 and housing 2302 from an electrolyte source 1970. The electrolytesource 1970 provides electrolyte through the apertures 2402 and intocontact with the substrate 114 during processing.

During processing, the balls 2204 disposed within the housing 2302 areactuated towards the polishing surface 2206 by at least one of spring,buoyant or flow forces. The balls 1906 are electrically couple thesubstrate 114 to the power source 1972 through the contact elements 1914and lower plate 2306. Electrolyte, flowing through the housing 2302provides a conductive path between the electrode 2462 and biasedsubstrate 114 thereby driving an electrochemical polishing process.

Zoned Electrode

FIGS. 24A-B show bottom views of alternative embodiments of zonedelectrodes 2500A-B that may be advantageously adapted for use with thevarious embodiments of the invention described herein. The electrode2500A includes a dielectric spacer 2590 and at least two conductiveelements. The conductive elements are arranged to create a plurality ofindependently biasable zones across the surface of the electrode 2500A.In the embodiment depicted in FIG. 25A, the electrode 2500A has at leasttwo conductive elements (three conductive elements 2550, 2552, 2554 areshown by way of example in FIG. 24A) that are electrically isolated fromeach other by the spacer 2590 to create zones, an outer zone 2524, anintermediate zone 2526, and an inner zone 2528. Each zone 2524, 2526,2528, shown separated by the dashed boundary 2580, may be independentlybiasable to allow the substrate polishing profile to be tailored. Oneexample of a polishing method having zone bias control is described inthe previously incorporated U.S. patent application Ser. No. 10/244,697.

Although the zones 2524, 2526, 2528 and conductive elements 2550, 2552,2554 are shown as concentric rings, the zones may be alternativelyconfigured to suit a particular polishing application. For example, thezones 2524, 2526, 2528 and/or conductive elements 2550, 2552, 2554 maybe linear, curved, concentric, involute curves or other shapes andorientations are possible for the conductive elements. The zones 2524,2526, 2528 and/or conductive elements 2550, 2552, 2554 may be ofsubstantially equal sizes and shapes from one zone to the next, or thesizes and shapes may vary depending upon the particular zone of concern.

FIG. 24B depicts another embodiment of an electrode 2500B having aplurality of independently biasable zones. In one embodiment, theelectrode 2500B has at least n zone electrodes (shown as two electrodes2502 ₁ and 2505 _(n)), wherein n is an integer of 2 or greater. Theelectrodes 2502 ₁, 2502 _(n) each include a respective terminal 2510 a,2510 b for coupling to a power source. The electrodes 2505 ₁, 2502 _(n)generally separated by a dielectric spacer 2506 or air gap. Theelectrodes 2502 ₁, 2502 _(n) may include one or more apertures 2508 tofacilitate interfacing with one or more conductive elements, such as theball assemblies depicted in FIGS. 14C, 14C, 18 and 23.

In the embodiment depicted in FIG. 24B, the interface between at leasttwo adjacent electrodes in not defined at a constant distance from thecenter of the electrode 2500B. Although the gap 2506 defined at theinterface between the electrodes 2502 ₁, 2502 _(n) (illustrated in FIG.24B) has a substantially zigzag pattern, those skilled in the art willrecognize that the gap 2506 may comprise any sinuous pattern (e.g.,curves or polygons). This allows the electrodes comprising the electrode2500B to be segmented into a plurality of zones, wherein at least onezone is defined as an area having a first percentage of area covered bya conductor and at least one zone is defined a second percentage (e.g.,different than the first) of area covered by a conductor, where theconductor may be the same or separate element. Thus, n electrodes can beconfigured to provide have at least n+1 zones of control. In theembodiment depicted in FIG. 2B, the electrodes 2502 ₁ and 2502 _(n),2502 _(n+1) are configured to provide 3 zones 2504 ₁ and 2504 _(n), 2504_(n+1) of control. It is contemplated that an electrode having a singleconductive portion may be configured to provide 2 zones of control.

The first zone 2504 ₁ is defined as the area of the inner electrode 2502₁ inward of the inner boundary 2580. The second zone 2504 _(n) isdefined as the overlapping area of the inner electrode 2502 ₁ and outerelectrode 2502 _(n) between the inner and outer boundaries 2580. Thebias over the second zone 2504 _(n) is controlled by the synergisticeffect of the biases applied independently to the inner electrode 2502 ₁and outer electrode 2502 _(n). The third zone 2504 _(n+1) is defined asthe area of the outer electrode 2502 _(n+1) outward of the outerboundary 2580. Thus, by controlling the bias applied to the twoindividual electrodes 2502 ₁, 2502 _(n+1), the bias of the second zone2504 _(n+1) may be controlled separate from the bias of the first andthird zones 2504 ₁, 2504 _(n+1), thereby allowing the polishing profileof the substrate to be tailor in-situ and/or between substrate tosubstrate polishes.

Thus, various embodiments of a conductive article suitable forelectrochemical polishing of substrates have been provided. Theconductive articles provide good compliance to the substrate's surfaceto promote uniform electrical contact that enhances polishingperformance. Moreover, the conductive articles are configured tominimize scratching while processing, advantageously reducing defectgeneration and thereby lowering the unit cost of processing.

While foregoing is directed to various embodiments of the invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A polishing article for polishing a substrate, comprising: aring-shaped upper layer having a polishing surface; and a conductivelayer coupled to the upper layer and forming a replaceable assemblytherewith, wherein a plurality of holes are formed through the upperlayer exposing an upper surface of the conductive layer.
 2. A polishingarticle for polishing a substrate, comprising: a ring-shaped upper layerhaving a polishing surface; a conductive layer coupled to the upperlayer and forming a replaceable assembly therewith; and a subpadsandwiched between the upper layer and the conductive layer.
 3. Thepolishing article of claim 2, wherein the subpad, the conductive layerand the upper layer are coupled by at least one of compression molding,staking, fastening, adhering and bonding.
 4. The polishing article ofclaim 2, wherein the subpad is fabricated from at least one ofpolyurethane, polyurethane mixed with fillers, polycarbonate,polyphenylene sulfide (PPS), ethylene-propylene-diene-methylene (EPDM),polytetrafluoroethylene polymers, compressed felt fibers impregnatedwith urethane, and combinations thereof.
 5. The polishing article ofclaim 2, wherein the subpad has a hardness between about 20 and about 90Shore A scale.
 6. A polishing article for polishing a substrate,comprising: a ring-shaped upper layer having a polishing surface; and aconductive layer coupled to the upper layer and forming a replaceableassembly therewith, wherein the conductive layer is stainless steel. 7.A polishing article for polishing a substrate, comprising: a ring-shapedupper layer having a polishing surface; and a conductive layer coupledto the upper layer and forming a replaceable assembly therewith, whereinthe conductive layer further comprises a plurality of independentlybiasable electrical zones.
 8. The polishing article of claim 7, whereinthe electrical zones further comprise concentric rings.
 9. A polishingarticle for polishing a substrate, comprising: a ring-shaped upper layerhaving a polishing surface; and a conductive layer coupled to the upperlayer and forming a replaceable assembly therewith, wherein the upperlayer is fabricated from a dielectric material.
 10. A polishing articlefor polishing a substrate, comprising: a ring of non-conductive materialdefining a polishing surface; and a conductive layer coupled to the ringand having a terminal for coupling to a power source, wherein a firstset of holes formed through the non-conductive material and exposing theconductive layer to the polishing surface.
 11. The polishing article ofclaim 10, wherein the conductive layer further comprises a plurality ofindependently biasable electrical zones.
 12. The polishing article ofclaim 10, wherein the conductive layer further comprises: a firstconductive element; and a second conductive element having an inner edgeinterleaved with an outer edge of the first conductive element.
 13. Thepolishing article of claim 10, wherein the conductive layer furthercomprises a plurality of electrically isolated concentric rings.
 14. Apolishing article for polishing a substrate, comprising: an upper layerhaving a ring-shaped polishing surface; and a conductive layer coupledto the upper layer, the conductive layer having a first zone and atleast a second zone, wherein a first set of holes formed through theupper layer for exposing the conductive layer to the polishing surface.15. The polishing article of claim 14, wherein the conductive layerfurther comprises: a first conductive element; a second conductiveelement circumscribing the first conductive element; and a thirdconductive element circumscribing the second conductive element.
 16. Thepolishing article of claim 14, wherein the upper layer is non-conductiveand forms a removable unitary assembly with the conductive layer. 17.The polishing article of claim 16, wherein a top surface of theconductive layer is disposed below the polishing surface.
 18. Thepolishing article of claim 16, wherein the conductive layer is disposedbelow the upper layer.